We rate limit accounts when they post too many low-quality comments too quickly and/or get involved in flamewars. Your account is rate limited because it has done a ton of that.

All is not lost; if you use the site as intended for a while, i.e. posting substantive, thoughtful comments that follow the guidelines (https://news.ycombinator.com/newsguidelines.html), you'd be welcome to email [email protected] and we can take a look and hopefully drop the rate limit.