Are they strife incarnate because they complain about something and then when it doesn't get fixed they complain about it some more? Or are you making the claim they complain about everything?
I ask this because I have met more than a few people who tried to say someone else did nothing but complain about everything but then when you got around them it ended up being a case of them complaining about one singular issue to one of the people who could do something about it and then when they ignored it and it didn't get fixed, the person did the only thing they could do, kept bringing up to their attention.
You can't really call those types out for calling shit out when it is the same shit each time and those who can fix it refuse to do so because at that point, there really isn't much else the person can do.
Too many people trying to use the logic "Not my problem" when many of the times it might not be your problem but it is your fault or that of your predecessor and you are the one with the power to fix it.