But then, how would criticism be possible, if the critic is everybody's (quasi) friend? And, after all, social life is, many would say, crucial to the art world.
If this is the case, the reviewer should clearly state his relation to the reviewed (e.g., degree of intimacy, number of conversations in the last week, month, year, common friends, social events both attended, etc.). I mean this quite seriously. This would also allow the reviewer to write more objectively, without worrying about the pain of hurting the ones we care about (and whatever you say, a bad review can hurt). It would make things clear: everyone knows about us, so I simply can't promote you. I can advise you, help you, work with you. I can listen to your explanations (which is already a great advantage you have). But this is where it stops.
And if it doesn't, if you resist everything but the temptation to "help" your friends, at least things are a little clearer for the public that is not in.