I really don't understand these grown adults angrily cursing at each other.

This sounds like a problem that could be easily solved by research. ;p

It's been postulated that swearing has an evolutionary advantage. Rather than express anger through physical means, swearing provides a different, safer outlet.

What I don't understand is why you feel so bothered by human emotion. Language, after all, is used to convey thoughts, needs, emotions, etc. Swearing has a place in that. Is it always appropriate"? No. But it's silly to suggest it never has a place. OP felt a strong emotion, she expressed it by using one or two f-bombs. You spend more time raging at her over that, than you do about the destruction of her property, which btw isn't cheap if it's what I'm thinking of. I have one of these swings and it was, oh, about $250? A woman whose husband neglects to gift her anything to the point of her kid noticing and feeling bad...yeah, that'll be a painful loss. He won't offer to buy another, he's an asshole himself.