YPYT tanks are literally inventing the pulling "role", courtesy of absolutely nothing official, and claiming they aren't the ones hindering play/failing to do their duties.
Here's the most that has ever been officially said about Tanks, as a role:
https://na.finalfantasyxiv.com/jobguide/battle/
Nothing there says anything about pulling. It IS explicit that you are to
- keep the foe's attention
And
- bear the brunt of enemy attacks
Now, I invite anyone ITT who defends/supports YPYT to find anything, in game or on the official sites, that says ANYTHING about responsibilities as to pulling. If you can find that, I'll keep my peace.
No, alleging that it is some sort of "unspoken rule" that tanks are "supposed" to pull doesn't change the fact that this is an unofficial term thrown on by the community. Nobody is bound to unofficial community rules; you ARE bound to the job description, just as much as a healer is to heal or a DPS is to do damage as quickly as they can.
No, liberal application/interpretation of vague statements about affecting others' play doesn't count, because if it does, by YPYTing you are the only one demonstrably acting against what little guidance we have as to role responsibilities, i.e. you are either or both of not keeping foes' attention nor bearing enemy attacks. Nothing there says anything about who initially got the foes' attention, just that you're to keep it; nothing saying anything about only taking attacks from enemies you feel like, just bearing enemy attacks (with what I should hope is the obvious unspoken fact of it being ALL enemy attacks, but I know this will be waved away).