Probably as a matter of convenience of getting into or out of hockey gear. They are in a locker room after all. Could also have just been more comfortable.
People be licking assholes and stuff and you are worried that there is too much sweat in the underboob? Babies don’t care. Boob sweat is the least of a kids concern. Hell, I’ve see a baby stick it’s hand in a poop diaper and then suck it’s thumb.
Why did she have to be absolutely shirtless?