I don’t think I’m being pedantic. In practical, the parent comment’s description is not that of MITM attack, but how a proxy works. Proxy is everywhere, useful, and voluntary.

I just don’t understand how a voluntary use of proxy can be called MITM attack.

I’m not saying I like the fact that CF is part of so much of the Internet, or that CF isn’t on some level a security risk. But that has nothing to do with being an MITM attack.