“Your browser might not be secure” is a worthless error message. If you have a strong reason to believe this is the case, you should tell me. If you don’t tell me, I’m going to assume you don’t have a good reason, and you’re just scaremongering.
They're not telling you what's wrong, just that you're bad for arbitrary reasons that ultimately will end up boiling down to "we don't trust that you try to preserve your own privacy".
