I didn't mind babies at the meetings. Moms were always good about walking out if the baby got fractious, and sometimes a friend would tell mom to sit and THEY would take the baby out so mom could have some down time.
I was uncomfortable with kids over 1 though, because some of the NA meetings I attended were pretty rough.
Usually moms got together and had an older sib watch little ones in another room, but that isn't feasible for a baby in arms.
I never heard anyone complain about babies.