I checked the rules and that was likely a penalty but I understand why they didn't call it - the receiver muffed the catch, and while an opponent cannot interfere with their attempt to catch the muffed punt, the penalty for doing so is the receiving team gets the ball at the spot of the fair catch. So nothing would have changed other than the refs throwing a flag.
Alternatively you could argue the receiver had already made the fair catch when contact was made, but that the contact was incidental (which is not a penalty at all.)
I checked the rules and that was likely a penalty but I understand why they didn't call it - the receiver muffed the catch, and while an opponent cannot interfere with their attempt to catch the muffed punt, the penalty for doing so is the receiving team gets the ball at the spot of the fair catch. So nothing would have changed other than the refs throwing a flag.
Alternatively you could argue the receiver had already made the fair catch when contact was made, but that the contact was incidental (which is not a penalty at all.)
edit: https://operations.nfl.com/the-rules/nfl-rulebook/#section-2-fair-catch for the dummies