The women at the weddings you went to ‘looked mental’, was a sloppy drunk’, ‘flirting with other people’s partners/husbands’.
You say yourself: ‘the brides were both affected by their attempts to make them look foolish. Even though they didn’t’.
Of course the brides didn’t look foolish! That’s my entire point. The only person who looked foolish was the ‘mental, sloppy, drunk, flirting’ mad women. Or the attention seeking MIL (pro tip, which the bride was obviously well aware of: if you think someone’s attention seeking - don’t give them any attention!).
But by all means, continue helping the OP to feel wronged and aggrieved.
Instead of pointing out that the ONLY person anyone will be judging is the person who made the faux pas. Not her.