Sort of ironic sending an abuse notification to a company that does precisely the same thing on a much vaster scale. And I would assume that the T&C for the new and improved Stylish that you accept when you install it informs you that you are giving them permission to do this, so there isn't even any abuse to complain about here.
I had this extension installed for years, from back when it was "still good". I don't recall ever seeing a T&C prompt, and in the last 3-4 years I've become quite vigilant about always reading full T&C texts (much to the amusement of others).
I was put in this tracking program without my consent.
It's particularly annoying, because I do have this Stylish extension installed (using css ::after rules to tag HN users)
EDIT: You can submit an abuse report when uninstalling a Chrome extension.