I agree with you on a personal level, though again I’m sure if I CTRL+F replika subreddit I’d find many people describing their emotions with similar words.
Anyway, let’s say he was negatively affected by that relationship, IIRC.
It's obviously dystopian to be in love with something that doesn't care about you at all. That is not, at all, what Her depicted. Sam clearly felt for Arthur deeply. Breaking up because their life paths were incompatible doesn't mean she didn't feel anything for him.
That made me happy, for once seeing AI getting what it deserves and dating other AI on its own level instead of being forced to "date down" mere humans. It was a story of emancipation for me.
I don’t fully recall the ending but doesn’t the AI grow past the guy and “break up” with him, leaving him devastated at the end?
A bit sounds like the Replika AI drama from the last year. </SPOILER>