A good opening would be, “I’m so sorry little Johnny isn’t being as quiet as he could be today. Perhaps you could have given me advice if it wasn’t so long long long long long ago that you brought your children to Mass.”
Wait, that’s not right. That’s what not to say. Try to remember that the person who quips as an aside usually does so because they lack the maturity to address a situation properly or lacks the grace to “offer it up.”
When someone offers you unsolicited criticism, sometimes you have to humble yourself for them to get a little humility themselves.
Perhaps you could try turning to the critic with a hangdog expression and open quietly with, “I’m so sorry little Johnny isn’t being as quiet as he could be at two years old. (Make an apologetic smile. Raise your eyebrows slightly and look hopeful.) After Mass would you take a moment and tell me how you were able to manage…with your children?* It’s so tough nowadays, and I’d love to hear your insights on this.”
(If they answer with, “I didn’t have any children,” you can say, “Ahhhh, I see,” and nod your head in understanding at their lack of patience. With a sweet smile, you can still press them for advice after Mass, if you’re up to it.)
Usually, the offender will either apologize or talk to you later. If you do get the chance to chat later, recognize that what you may hear may not agree with your idea of parenting, and recognize the humility it takes on their part to answer for their rudeness in a very Christian manner.
Ask leading questions. If you are told that, “Punishment should be involved if they cannot seem to sit still or cause a ruckus,” ask them how they were able to punish a toddler at Mass without exacerbating the situation. Draw them out. Be sincere, be curious. They probably just need someone to listen and show an interest in their experience.
I know this won’t be easy with everything you have to carry, but ten minutes chatting will win you an ally and put you both at ease.
Guess what? The best case scenario is that you’ve probably just made a friend who needs to be reminded that a little discomfort on their part is an opportunity to help themselves – and others – to grow spiritually. That’s my idea of Catholic community.