I'll put on Emongg's vod review videos on as background noise, and pretty often when he's reviewing tank games he'll say something along the lines of "teammates who don't know how to play tank will tell you how to play tank," and that really helped me with not giving too much weight to the whining. 

Like, *you* already know when you made a fuck up. But your team will call everything your fault. They got headshot because they peaked a sniper angle when they didn't need to? Your fault for not being a barrier bot. They got dove because they stayed too far back? Your fault for not being with the team. Etc, etc. 

Asking for a specific tank for a specific reason is one thing, but "tank swap" without any other information, or "tank stay with the team" when it's not appropriate to do so is just people telling you how to play tank when they don't know anything past surface level because it helps justify to themselves that *they* aren't part of the problem. It's just the shitty tank, and I'm *helping* them!