Literally the entire point of pronouns is defeated if people don't know what pronouns a person uses (and this applies to more than just trans people too), so there is some use for people that put them in their name.

Beyond that though, even if there's no need to say or publicly display something, that doesn't mean one shouldn't say it, and it definitely doesn't mean one should be forbidden from saying it. There's no need for people to tell me about their hobbies, or wear t-shirts or put up bumper stickers with messages on them, or put up religious symbols everywhere. Perhaps I'm tired of seeing messaging for political candidates I don't like, and wish they'd keep their preferences to themselves, or perhaps I don't care if people are married, they could just keep it between themselves rather than wear some rings to tell the world about it. But you know what? If I were to support making it illegal to say and show and wear an express such things, especially on the internet where the stakes are even lower, I'd be closer to the leader of something like the Taliban or North Korea, than to a good citizen of a democracy.

Even if you think saying/displaying/supporting something is "attention seeking", well, people have a right to do that. To try to restrict that would be to restrict the right to free speech itself, because you cannot communicate with someone without first getting their attention.