To be clear, I'm not making accusations about Vietnam, I was just thinking about it and found it a little strange.
I can think of some fairly plausible reasons, but just because those reasons are plausible doesn't mean they're actually correct, so I was wondering if anybody had a more concrete historical and materialist understanding of the situation.
The DPRK wouldn't hate america if america allowed them to trade.
The situation with the dprk is entirely caused by the north/south divide issue. The US continues its war against the dprk because it wants a unified capitalist Korea and supports the south.
If the South didn't exist there's every possibility the dprk could have ended up with relations similar to vietnam.
If the Vietnam had ended up split into north and south their relations would likely be in exactly the same place.
Material conditions drive these things. Not vibes or morals or anything else.