What are you trying to achieve here? Your entire domain will just end up blocked if you do this at scale, not to mention Google themselves would ban your reverse proxy’s IP because of too many queries (since you’ll be proxying all your visitors’ requests from a single IP).
However this example is a bit different, the site in question is going out of their way to being a reverse-proxy for a spyware command & control server, and the entire domain should be considered & blocked as such.
If you're talking about them selling the data gathered by these, then that'd be less common but certainly not unheard of. If you're talking about them doing something more nefarious on your machine (keylogging/cracking) then hopefully that's pretty hard to do against a modern browser and any site caught doing so would never get any traffic from me again.
The problem is that the site is now serving a piece of (third-party, but that's besides the point) malware explicitly designed to monitor events that would normally not cause a network request (and thus wouldn't be logged), and then sending that to a malicious third-party through a reverse-proxy.
The problem is that creating reverse proxies on random domains is too easy, by distributing this to different domains it wouldn't be possible to block this effectively!