I mean I realize it probably isn't a problematic, just wondering, but on the other hand it shouldn't be so difficult to follow the reasoning based on the context I would think:

poster says - in order to be able to scrape effectively you should appear to be a real human, use different UAs etc.

So as this change happens different UAs become one less thing that you can easily change to seem less suspicious, as a non-frozen UA would then be a suspicious sign after some time.

So a sort of side effect.