Free hosting has been a thing for a long time. I remember having some free PHP4/MySQL hosting and they gave you like 50MB of storage space for your stuff 20 years ago.
GitHub pages and others all have some terms saying what you can and can't host using their services. It makes sense for Intel as it's an open-source project and fits GitHub's goals. People can contribute to the website on GitHub, and when the PRs are merged it gets deployed automatically.
If you're any sort of serious about your online presence, it makes sense to pay for hosting because that comes with more features, support, and certain guarantees about performance and uptime. If your business relies on it, even if it's just a static site with your phone number and email on it, why not throw in that $5/mo on a VPS or a hosting company that's contractually bound to provide the service to a certain level?
If everyone used free hosting whenever they can, it would become too expensive to run and provide for free. Most hosting providers that provide a free tier use it as a lure for you to grow into their paid offerings. Like, basic Cloudflare is free but downloads and video streaming through their free tier is technically against ToS. You need a paid plan to do that, and get more caching capacity, more uptime guarantees (CF basically rolls things to free tier first as if it breaks, it doesn't affect paid customers so you're doing free testing for them).
Free tier makes sense for individuals to learn and stuff, and I greatly appreciate having had access to free hosting for a solid 10 years. But I've moved on, I can afford my own servers, and there's nobody to go under and shut down the service or tell me I have too much traffic and kick me out. You get what you pay for, after all.