> I am not certain I believe it is very likely, because (a) I think "sign-in partner" is obvious bullshit, and (b) I don't understand why I would never enter a code into the wrong website. I believe it can be possible, but...

You and I think they are bullshit, but ... the problem is that bullshit is sometimes genuine.

I have got tired of how many times in recent years I have seen things that looked like phishing or had obvious UX-security flaws and reported them only to have got a reply from customer service that the emails and sites were genuine and that they have no intention of improving.

If janky patterns is the norm, then regular users will not be able to recognise the good-but-janky from the scams.