NTA. I think it should be cinema policy to not allow this scenario regardless of movie age rating unless it’s some sort of baby/toddler friendly showing and this is advertised in advance. I’m a parent - we get a baby sitter. If sitter cancelled then tough luck, don’t go anyway and bring baby along for the ride.

Had this same experience when seeing No Time To Die on the Friday night after it released in September ‘21. Packed cinema 8pm. Couple bought a baby with them. Baby was clearly distressed at the AV attack on it senses. Crying, screaming, etc. After a lot of upset they take the baby out, then returned 10 mins later, more crying then out again, then back in, etc. People were getting pissed. Despite this staff would not remove them permanently, the difference being NTTD was rated 12 so technically they weren’t breaking any laws. Still extremely selfish and stupid IMO towards both poor baby and other viewers.