A whole season for betting that didn't compromise anything, but only 4-8 games for the cases of domestic violence. Makes sense.
Absolutely it makes sense. One affects the integrity of the sport, one does not.
I think most people would prefer to see domestic violence punished more than gambling
In society, absolutely, but not on the field. In fact, I've argued that off field things have no bearing on sport and shouldn't be regulated by the sport at all. I realize I'm in the minority of that view, but the league shouldn't get involved in an employment matter between the player and team. Things like PED's, gambling, deflated footballs (ha), etc. affect the actual on field results and those things should be regulated by the league.
I always look at this way with my own license in my mind. There are absolutely certain crimes that if I commit, I should lose my license, but most crimes have no bearing on my ability to perform my job, and thus I shouldn't lose my license if I were to commit them. That said, many of those crimes, I'd get fired for committing even if I didn't lose my license. That is the way sports should function. I suspect the league has stepped in because the teams don't want to have to make that decision, but for me, I'd rather just see the league not do anything and leave it up to the teams to decide.