Well, it is only because boxers wearing them tend to hit that much harder. We won't see someone punching like that without gloves(no one wants to break their hands/fingers). The gloves themselves don't cause brain injuries, it is the force behind them.
I doubt UFC fighters are swinging any less hard so that's not really a reason why boxing gloves would supposedly cause more brain injuries than MMA gloves.
I don't see why boxing gloves would cause more brain injuries. I think there are likely better explanations.
I would wager it has to do with getting hit in the head a few hundred times in a single match versus a handful. Maidana landed 230 power punches against Broner not too long ago.
Or just the sheer number of bouts. Tito Ortiz has the most UFC bouts at 27. That's almost halfway to Ali's 61, and about 1/7th the number of fights that Sugar Ray Robinson had with 200. It'd probably take the average UFC guy like 10 careers to get to 200 fights.
Sparring in boxing means your taking hits even if you have headgear on. UFC fighters practice multiple disciplines so don't get hit nearly as much while training.
Or the fact that getting knocked down doesn't necessarily end the fight if you can answer the 10 count, only to take more punishment. Or that you don't have to be knocked out in order to lose in the UFC as you could be submitted. You may not even get punched in a UFC match if someone makes you tap soon enough.
Or maybe it's because the UFC hasn't had a long enough lifespan to see it's fighters become eligible for social security and show the world what getting beaten in the head for a lifetime will do to someone's brain. To go along with that Boxers typically start well younger than MMA have, primarily because MMA had been recognized as a sport in the manner that boxing was for quite some time. Younger guys getting beaten while they're still physically maturing, and then getting beaten until basically they lose so many fights that they are forced to retire after a career that could span over 20 years.
Sport Science compared the two gloves and didn't find much of a difference. Granted they had a UFC fighter punching which may discount added power that a boxer may have because of technique and skill but this wouldn't be a reason why the gloves would cause more brain damage, simply a reason for why boxers get more brain damage.
Here's the video.
