@SillobreMVC 1. It's a moderation action that a mastodon admin, assumedly mamot has put on your account. Yes, it was on purpose, possibly due to a report one of their users made on one of your posts.
2. People don't know about it because most people aren't administrators or moderators so they don't see the backend of things like this.
I'd say the only way to know for sure is to message the admins, in this case it'd be LaQuadrature. I'm not sure if they'll respond though. Most admins or moderators don't respond to users that they've blocked or limited.