Well, that's precisely what is sinister here.

Those profiling tools don't really care which features are going to be used for predictions. It's just machine learning, and it's indiscriminate. So if you have an extension that correlates with you being Muslim, it will be used for whatever ML predictions they give to other companies, and the worst case will be another "oh we didn't do this intentionally".

Of course, that's not the first time this ever happened in human history, so even if it's not "something inherently sinister", it's just "criminal negligence".