This whole thing is simply a new manifestation of the elitism syndrome that has always plagued KSP. Any suggestion that a player should be forced into a more (or less) difficult condition that is otherwise optional because a different player thinks that difficulty is fun is obnoxious.
KSP, like any game, should be about enjoyment. If you enjoy high levels of repetitive difficulty, rejoice in the fact that you have that option. If you enjoy playing casually, rejoice that you have that option. Fortunately, at least until now, Squad and Private Division have had the wisdom not to do something so asinine as forcing any particular difficulty options on anyone. Let us hope the new developers retain such enlightenment.