Upset about how a single moment escalated

I recently had a small wedding solemnisation with both families present. Overall, the event went smoothly and I thought everyone had a good time.

At the very end, after I thanked everyone for coming, my mother spontaneously added a short comment thanking my wife's parents for raising her into the woman she is today. It wasn't a planned speech, just a brief remark made in a celebratory spirit.

Afterwards, my wife told me that her mother and sister were quite offended by the comment. Apparently they felt it was inappropriate for my mother to say something like that, and there were also comments made about my mother's character.

One remark that particularly bothered me was my wife's sister asking whether my mother was a housewife, then responding along the lines of "ah, that makes sense" and describing her as a "Karen."

For context, my wife has a complicated history with her family. She moved out a couple of years ago following conflict with her mother and has not moved back since. There are a lot of unresolved feelings there, and I can understand how comments about parenting or family might hit sensitive spots.

What I'm struggling with is the sheer gap between intent and reaction. From my perspective, my mother was trying to be gracious and appreciative. The response felt far harsher than the original comment warranted, especially when it quickly turned into judgments about her personality.

I also find myself becoming increasingly resentful of my wife's sister. It's one thing to dislike a comment. It's another to make broad conclusions about someone you've barely interacted with. I feel protective of my mother, and hearing these things second-hand has honestly made me think much less of my wife's family.

Part of me wonders whether I should simply stop caring about their opinions. Another part of me wonders whether that's just a defensive reaction because I feel my family is being unfairly criticised.

There's another layer to this that bothers me. My wife's sister was significantly late to the solemnisation itself and missed most of the actual ceremony. She arrived essentially in time for the meal and never apologised to me. My family viewed that as quite disrespectful. Yet somehow that generated far less discussion than my mother's one-line comment.

My wife agrees that my mother didn't mean any harm, but we've been trying to discuss how to prevent similar situations in future and keep getting stuck. Any suggestion seems to imply that my mother did something wrong, which I don't really believe.

For those who have dealt with difficult in-law dynamics, how do you handle situations where one side interprets a well-intentioned act in the most negative way possible? How do you stop yourself from developing long-term resentment towards people whose judgment you fundamentally don't respect?

And is there any value in hearing these criticisms at all, or does it just create unnecessary anger?