Is there a reason for that, other than "because we can, screw you?" Amazon owns freevee, right?
It’s an experiment to understand other ways of making money. I also believe freevee is available without prime video.
I was saddened to find a few years ago that some of my favorite shows on playlists were moved from then ad-free prime to the ad-infested freevee (e.g. Allo Allo) - made it a no-brainer to not renew after the year expired.