Of course, Luck should do what he thinks is best. It is his life, but....
1) I didn't like that he focused on mental health. I think it was more the physical injuries so not sure why he didn't focus on that but getting your mind right is part of being a franchise QB.
2) I fully understand why the fans are upset. A franchise QB has a lot more expectations and responsibility than any other player in the organization. If he could physically be a backup QB this year, then he should have stuck it out and/or allowed the team to make the decision for him to retire or not. Now maybe he couldn't; maybe his body is in such bad shape that he can't even be expected to play 20 snaps a game but then the question is why didn't anyone in the organization figure this out earlier? The situation doesn't make sense.