There we go you all finally said it - comfort and no danger. You participate in BGS and Power Play which are both Player vs Player activities but don't want to actually meet the other side. Also if you run a block list you just make Open another Private group because of the way instancing works. That's so fair and balanced - got it!
There is no danger in this game - as explained earlier, twice. Each player chooses how they want to play the game - and they don't need to take other players' desires into account.
We all affect the BGS and Powerplay, by design - as both features were implemented for players in all game modes. The existence of the three game modes sharing a single galaxy has meant, from the very beginning, that other players (and therefore PvP) are optional extras that no player needs to choose. Player driven does not mean "requires players to engage in PvP".
Not sure why players in Open having access to exactly the same tools to affect the BGS and Powerplay as players in the other two game modes is perceived to be in some peculiar way "unfair" - unless the "unfairness" relates to not being able to force other players to engage in an optional game activity to satisfy the out-of-game ruleset of a subset of the player-base.
If was Frontier's choice to implement the block feature before the game launched - as they foresaw a need for it. It has only been strengthened and made easier to use over the years, presumably due to observations of the behaviour of how some players choose to play the game.