Boxing is far worse than other combat sports because of the thick gloves, and plenty of combat sports don't involve significant head impacts at all.

The equipment to make it safe is the problem - it allows you to take orders of magnitude more blows to the head. There were many people saying that to improve the safety of football, you should get rid of helmets entirely.

Padded helmets in football and padded gloves in boxing serve the same purpose as having filters on cigarettes. Filters on cigarettes allow you to smoke a lot more, and a lot of the stuff that is worst for you is not filtered out.