Diplomacy is a great board game but only play it if you're OK with your relationships coming to an end.
I used to betray my friends and supply there enemies with weapons and research support in Civilization way back when. If you can't stand being lied to and betrayed, you shouldn't play strategy games with humans. Or this AI, probably.
It is a thing that happens. I don't think it speaks to the depth of their feelings, it speaks more to how they develop trust.
Some people prefer the happy lie over the uncomfortable truth.
Different strokes for different folks. Diplomacy is a great board game if you accept your friends are flawed ugly human beings, and you can love them anyway, same as you.
Ehhh I think what OP means is that this game can surface known or unknown tensions between friends and colleagues.
No friendship is bulletproof, odds are even your best friends annoy you sometimes.
I saw two 'best' friends basically scuttle their friendship during a game of Diplomacy about 20 years ago, so I've seen this first hand.
It turns out these lifelong friends had all manner of unresolved issues, that perhaps they could have worked through with intention, but a particularly ruthless game of Diplomacy brought it all out in an uncontrolled manner, and that was that.
So yeah, people are complicated and messy, and I don't think the issue at hand is "being lied to and betrayed in a game".