It's not clear until you explain it precisely, and even then, it remains quite vague: are we talking about griefers, or about anyone that does something you don't like?
Still, if they're people being a problem, again, they're only dealt with by facing them, and avoiding them will make it worse, and while, again, it is grossly exagerated, it could very well become as bad as some think it is if it keeps on being avoided. So in fact, you're talking about something that doesn't quite exist (and depending on what you really mean, might not exist at all), and that is made worse by being avoided. How does it change anything?
Exaggerated or not - and we won't know the full scale of the problem until the game goes live. Whether you agree that the problem exists or is valid in your opinion is moot - the only opinions that matter are those of the affected players - to allow a group of players to block other players group switching because they do not consider there to be a problem would be favouring one group over another - something I do not expect Frontier to do. Any player who is sufficiently put out by the actions of other players to want to group switch can - that's the beauty of the freedom offered by Frontier.
They don't have any responsibility, it's not their presence that is the problem, it is both expected and needed, but the absence of some others which are supposed to counter theirs. We know how to deal with them, and you're part of the solution, it's only up to you to step forward. Their existence is a normal thing, but your absence isn't quite so, and it's not about changing, it's about being present, so the community is a perpetual face off of the different playstyles which counter each other and eventually even each other out. To balance a community, you don't exclude people, you attract others.
So, the presence of players whose play-style is considered by some to be at odds with theirs to the extent that the latter wishes to group switch is to be expected and tolerated? Asking the less combative players to "step forward" is merely asking them to play into the hands of the more combative players by adopting a more PvP oriented play-style - again, one group does not need to change, but the other does....
.... and yes, it is about changing - you seem to contend that players who would wish to play outside open should change their minds and accept anything that happens in open including those players that they would wish not to encounter because "Their existence is a normal thing" - someone is having to change their game and you're not proposing it is those who some wish to avoid.
But then, we might aswell start giving names: how many griefers are there really? Even then, just give me their names, I'll hunt them down, like I chased a couple pirates just yesterday, allowing other commanders to exit the station safely: it was unscripted, unexpected, it just happened. Because that's what you do among a community, you identify your enemies, call for your friends, and face them: everyone got what he wanted, the pirate got a fight, I got a bounty, traders got their safety after a tense moment, and that's how things usually work, and how I hope they'll work in Elite: Dangerous.
Who knows how many there are? There are those who have never seen any - there are those who have had unpleasant encounters that they consider to be griefing - there are those who look at those encounters and say that it was not griefing - there are many opinions as to what does and does not constitute griefing with no definitive, agreed, definition. Creating a situation where players who do not crave PvP action are encourages to play in open and may be subjected to it - only to feed the need of others to be called in as defenders is a bit tenuous (the galaxy is big - the likelihood of a player defender being available in the vicinity is too small to count on). I'm glad that you're enjoying your choice of play-style - it's not the only one out there and other players will no doubt make different choices (and not necessarily with to be dependent on others to enjoy their game).
Obviously there is no obligation, but then you can't just act like your behavior won't hurt the community, because it will. You need to choose between considering it an obligation, or facing the responsibility of ruining the community, and you won't escape that choice by hiding into a group. It still doesn't change that it might not be worth it to play in a group at all, when people in open complain well enough about not meeting anyone, and when your presence could solve so many problems, including your own, by making open play a place enjoyable by everyone. So no, I didn't miss the point, I'm only questioning reasons for solo and group play, considering pretty much all those mentioned range from exaggeration to lies, and when that happens to put the whole community at risk, it worries me.
You seem to be of the opinion that the only behaviour that will adversely affect the game is that of the players who do not wish to be in the same game as players that they wish to avoid - you seem to consider that the players whose play-style may upset other players have carte-blanche to carry on regardless of the effect that their play-style may have on the game. If there is no chance of the more extreme players changing then adding unwilling victims to open is not going to cure anything - it will only satisfy the more extreme players by giving them a larger herd to cull.
You talk about community and talk about some elements making the effort to improve it while in the next breath (paragraph or post) defend the "rights" of the more extreme players to play how they want to with no regard for that community. Odd.
The idea is that why that happened that way is completely beyond your understanding, and that it would be quite a waste of time to focus so hard on it.
How any player gained their assets is, while not beyond understanding, still of no real consequence - there are many ways to do so - some earned, some gifted.
Regardless, the idea is that this is quite a minor issue, and even then, a minor issue of one of the outcomes of something that hardly ever happens. I would run out of synonyms for "rare" and "uncommon" pretty quickly if I were to explain the chain of events that would lead to such a situation.
You still can't say never - and that is not enough for some players who have no wish to have their game spoiled (in their view) by the actions of others.
All I'm saying is, open play can be a great place for everyone, but everyone needs to join for that, so that the balance doesn't shift too much towards one playstyle. Avoiding griefers is the only proper argument, and even then its existence is discutable.
.... and I sincerely hope that it is a great place for everyone - but everyone needs to want to play there, not be forced to play there. As to what constitutes a "proper argument" - that's your opinion - other opinions vary.
After all, as it stands, no one really needs to take care of the griefing problems, but the community has no safeties, and the first few days after the release will make or break it.
Indeed - the more extreme players could tarnish the game for many new players at the outset.