This behavior first appeared months ago, sporadically, with certain stores. More recently, it has become much more prevalent, site wide.
Some speculate that it’s an effort to prevent spiders from scraping info off AX, which I guess is plausible, but the site is already so convoluted in the way it and the sellers list items and variations, that would also require a heavy effort to parse that information.
Personally, I’m not going to log in, or show my ID to any store I’m going to window shop, whether online or B&M.
If that’s the way they want to conduct business, I’ll just stop browsing AX, and the sellers will lose out on any possibility of an impulse buy.
Not going to bother complaining to AX’s circular-file-shaped suggestion box. But next time I do transact with a familiar and valued seller, I will note to them that this practice has an effect. AX may not heed sellers any more than it does buyers, but at least the seller will know why they’re not getting as much business from me.