That’s incorrect.

BlueSky relies on JavaScript to run (try turning it off and loading their site, it won’t even render). Click-through traffic is almost exclusively measured by JavaScript (e.g. Google ad “events”). This is the same as measuring other stats, like whether you lingered on a post before scrolling past it, or whether you opened another tab, or whatever.

Proxy links are absolutely a method of measuring traffic, and they’re a method that works even when the site has JavaScript disabled - but since that’s not how Bsky works, it’s not relevant.

The big reveal comes when you realise the paths are in fact, relative.