Exactly, the server shouldn't ignore it, the user via the client should do it if they wanted to.
I don't like the fact that @Mastodon has basically stalled the development of the fediverse, people here are way to afraid of breaking stuff. Don't get me wrong, backward compatibility is cool, but sometimes you gotta do it for the benefit of the whole net.
I've read about some cool FEPs that are basically ignored out of the fear of incompatibility with Mastodon or older versions despite de fact they solve a huge problem.