It doesn't matter who you (claim to) represent: bans are personal, they're not limited to an account, but to a person. If I'd get banned, I wouldn't be allowed to create an alt and then say I represent the pope. I think you completely misunderstood how bans on Bitcointalk work.
Well, okay, let's imagine for instance that Tether comes to the forum and opens its topic to share news and answer questions. They hire one representative after another and this goes on for some time. Then it's revealed anyhow that one of those guys they hired was a ban evader during he worked for Tether as their representative. So we say that it was a violation (it was, I don't say wasn't) so we ban an official account of Tether for ban evasion. Moreover it is not an account banned it is a person behind it banned so Tether is forever banned from using this forum. Moreover we find somehow all people who worked for Tether during that time (at least all who worked with that account after ban evader) and we ban also them because they worked in an offending account, and also ban them forever.
You know, maybe it is how all the things are really go on, but if so it looks so wrong! Right because the person is banned from the forum and not an account.
And after all we ask, why projects decide to represent themselves on the forum much rare then previously. And really, why?