[cowsup]

HTTPS also prevents your ISP, your government, or other people on your network from viewing (or, in rare cases, modifying) the pages and content that you browse.

So no, a blog post talking about ray tracing doesn't inherently need to have HTTPS, but it's a good practice for any and all websites to implement it, to protect user privacy and prevent tampering. Nothing bad is likely to happen if you read that site, though, so don't worry about it if you're just a regular user.