> Why would anyone expect anyone else to serve video for them for free?

I would expect that a freemium service selling encrypted "zero trust" networking should have no idea what traffic is being pushed through my network making enforcement impossible.

Nobody's asking for a free lunch, but the reasonable thing to do would be to simply bandwidth limit freemium accounts across the board, not make exceptions for certain kinds of traffic in what should be a secure network.

But those are different services. You linked the CDN TOS.

(I can, in practice, serve small amounts of video through the free CDN, by using HLS; I'm also aware that this needs to stay below the radar)

Cloudflare does say "video and other large files" so in the end it is about volume, not data type. They probably just want to have the arbitrary decision on specific cases without defining a uniform blanket limit.