Anyone trying to infect others with Trojans and viruses just need to check user agents or use dynamic redirect URLs, and suddenly this clearly illegal activity becomes black magic that is way beyond the comprehension of the folks at Cloudflare.
Cloudflare is basically making the shittiest parts of the Internet safe for scammers and spammers, and this is just one example.
If that's not bad enough, they're trying like crazy to become a monopoly. If this what they do now, imagine how bad it'll be when they control even more and feel even more immune to making money from scammers.
(1) Hosting is providing services on the Internet without which a site would not function. Providing DNS is hosting. Providing proxy is hosting. Providing email is hosting. Don't fall for Cloudflare's "we don't host" bullshit.