Cloudflare runs DDoS protection against a surprisingly many sites now. Often you don't even see the "checking your browser" screen, it just happens passively.

While individual authors and publishers benefit substantially (caching, anti-DDoS, etc.), this is a huge net loss for the internet. It essentially entrenches Google and the rest of MAGMA as the forever winners of spidering the web. If you try to spin up your own crawler, you'll get hit by this bullshit. It's becoming impossible to bootstrap now.

The usual method is to let Cloudflare collect that data passively, I like the honesty of letting the user see the DDoS protection in action better.

At least this website doesn't require a captcha when you're visiting through TOR, that's better than most websites behind DDoS protection.

Was that not a proxy doing DDoS protection?

Like most of the modern web, yes.