All fair and expected points, here goes:
1. The core value offering from this game is a simulated future universe. There are games available today that allow the user to simulate the of women - also not real life, but extremely distasteful and not something I enjoy. My enjoyment of this game is not contingent on the presence of institutionalized slavery in the game, it is hampered by it, and it is not a necessary mechanic to allow my continued enjoyment of the game.
2. I actually do get how it works, I read up on Imperial Slavery before I made the post. Keep in mind that there are two commodities in the game as well, my comments are not exclusive to Imperial Slaves. Saying "Indentured Servants" is a lot different than saying "Slaves", because of the historical associations with and legal definition of the word "slave". If you don't agree, we will just part ways on that.
3. This is a good point, which is murky due to our already existing moral relativism on the issues of murder/drug dealing/piracy/etc. I'll cover each since you mentioned them:
- Murder: I'm not sure this actually happens in the game anyway, because after I "kill" an npc they are usually back for more later. If you "kill" another player, they eject and show up in a new ship. You're not really killing anyone in the game. But even setting those things aside as game mechanic realities and pretending that you're killing them in the game, the penalties for someone who chooses to be a mass murderer are extremely high and obvious compared to those who transport illegal goods. The dis-incentive is a lot higher for this behavior. You can not implement measures to avoid a bounty if you kill a clean player or npc. You can use countermeasures to avoid getting caught in trading.
- Smuggling illegal goods: It's possible to calculate the human misery and knock on effects from transporting arms and drugs, and the punishments/risk in game appear to be of an appropriate scale to the crime - the negative effects of those items are also secondary to society, as they require a consumer that is using them for ill will. Trading pods with humans in the in the game has a direct effect, but the player's risk is about the same as these other items, and furthermore, trading in those items appears to be more profitable and popular than other illegal goods according to the dozens of youtube videos available on the subject.
Those points are secondary to the crux of the issue, because I acknowledge that violence is an acceptable part of a game that simulates combat and a struggle for acquiring territory, and I think that no matter how evolved we become as a species, there will always be a market for war and pharmaceuticals. This is ubiquitous in gaming. we can play games to be a hitman, an assassin, a soldier, and so forth. Only a very few people are unable to separate and compartmentalize the actions taken in game against actions in the real world, and because that is commonly understood and accepted, I'm okay with it. Maybe 100 years from now people will look back on this as the Dark Age of Violent Gaming. I don't know.
So why can I not just bundle ED's slave trade in with that stuff? 1. Because it's unnecessary to promote enjoyment of the game unless you are specifically playing it because you like fantasizing about trading slaves, 2. because its implementation in the game is culturally institutionalized in the lore to the point where I'm playing in a universe where I have to accept that slavery is just an acceptable part of life to the plurality of the game universe's inhabitants, and 3. it's cost/risk ratio is high enough that it's a preferred method of progressing in the game, so it teaches an in-game heuristic of "trading slaves = good".
4. I hear this point, but we don't currently have artificial sentient beings mixed in with human society, and many authors of science fiction have explored the issue of what it means to be alive and sentient, and what natural rights machines have if they are or appear so. There is no consensus. Take Star Trek. The Federation wrestled with whether or not Data was alive, had the right to reproduce, and looked at other explorations of artificial sentience by character proxy. You appear to have concluded that if an artificial life form appears intelligent and sentient, then it's wrong to buy and sell them as a commodity, in which case you don't have to, but the ethics are hypothetical and broadly inconclusive, whereas the ethics of doing such with humans is already well established. Taking both at face value, which would you prefer to have in the game as an option?
I suppose that what it comes down to is that I don't understand why it is even in the game when it is not really necessary for enjoyment. There are a number of other possible things that can provide a black hat guilty pleasure for gamers wanting to be a bad guy that don't trivialize, if not provide incentive to act on, what is essentially an activity that is a source of societal pain and disfunction that we're still living out today.
I'll add one additional thing: if I owned a gaming software company, I'd be concerned about the prevalance of videos associated with my game that shows up when you search for "slave trading" on youtube.