IANAL, but I don't think there's a reasonable ground for a lawsuit (although there's nothing prevent an attempt). It's not claiming to be TikTok, that would be a clear trademark infringement. It's just saying it's similar to their service, and if you want to compare it (which is allowed), you have to refer to it somehow. Similar to when people say LibreOffice is an MS office alternative - Microsoft wouldn't have the grounds to sue there, either.

Make a PR to replace it with "Shortform"