What do you think "low quality" means if not "what people don't like"?

TikTok doesn't care who made it; they care how the video looks.

This isn't about content being low quality or not liked. It's about content containing specific things that TikTok moderators were told to look out for.

There is plenty of extremely high quality content made by people who appear fat, poor, old, disabled, ugly, etc in their videos.

So, like reddit?

Moderators of the subreddits in reddit are normal reddit users (normally) compared to the moderators in TikTok who I presume are selected by the company and on payroll (or contractors maybe, I seem to recall Facebook uses contractors for this)

Paying their labor seems to be a respect in which TikTok is better than reddit, not worse.

What difference does it make? People are moderating content that they want to seen or not want to be seen.

No different than the editor of a newspaper or television show.

I don't think Reddit gives moderators instructions to remove content if it indicates that the poster has a list of undesirable characteristics like being fat or poor.

So, like Facebook, Twitter, YouTube..?

Facebook, Twitter, and YouTube don't have moderators hiding posts by fat or ugly people.