If playing during this pandemic removed the other problems that come along with playing football, I would agree with you--the risk to the players alone would be less.
But, that's not the case. COVID is just one more problem you have to throw on top of the heap of issues that NFL players face.
Then you have to realize that we're not just talking about players. We're talking about everyone involved in the NFL. We're also talking about the social circles those individuals find themselves in outside of the NFL.
I think baseball has a decent chance of finishing because you have guys playing every day. There's a good chance they don't have much time to go out and bring risk into the circle that is the on-field competition, especially when they're on the road (But hey, Clev and Plesac sure proved us wrong there!). However, the rosters in football are larger, the staffs are larger, there is more physical contact, and then you have a week between games. It's a pretty sloppy recipe.