AFAIK a lot of linux packet repositories are http-only as well. Convenient for tracking what package versions have been installed on a certain system.
Package managers generally enforce authenticity through signed indexes and (directly or indirectly) signed packages, although be skeptical when dealing with new/minor package managers as they could have gotten this wrong.
Saying it's "fair" is like saying engine maintenance does not matter because the tires are inflated. There are more components to it.
Ensuring the correctness of your entire stack against an active MITM is significantly more difficult than ensuring the correctness of just a TLS stack against an active MITM.