Without context it's impossible to evaluate your complaint. If it was an anonymous and anodyne profile as you say, what was personal about it? I'm sorry you had a bad experience but, but with so little to go on about what actually happened I can't form an opinion.
Your headline is something of a loaded question and you just created a new HN account to talk about your bad experience of creating a new Mastodon account, and announce your lack of interest in social media based on an interaction that only you know the details of. I'm not sure what you're trying to achieve here.