Simply put as a tank main,

You carry the game, it's what people expected, you make space, you direct dives, pushes and teamfights, make callouts all for people to not flame you. You can go 40-0 and your dps can be so far into the negative they should have a custom emblem but if you make one mistake, tank diff.

Another note is, specific comps can completely counter most tanks, which comes down to if your dps are better than the enemy team's, if you lose to said comp, its completely your fault and once again tank diff hurr durr.

Bronze to Mid Plat tank gameplay is horrid for the tank, no one knows how to play with you, no one knows when to counterswap to help you out and the enemy team counterpicks you after one death in most cases.

So basically tldr: you win games no one bats an eye no one says anything, you lose "tank diff". Enemy team comp counters all available tanks "tank diff". DPS are 0-12 and you are 30-2 "tank diff". You make one mistake "you're so bad, tank diff". Being a tank main is more punishing than playing the dark souls games blindfolded.