Specifically, Biden didn't seem happy about not fighting North Korea, and unspecifically he was giving her "massive bad vibes".
Probably the bad vibes of absolute weakness and insincerity.
I would categorize this friend as someone who would vote for Bernie or Yang if they were close to winning, promised to legalize weed, and there was also peer pressure from certain Bernie bro facebook friends. Some people just want weed and no war, and Biden gave her flashbacks to Hillary's warmongering which kept her up at night with anxiety at the time.
"OMG NOOO not this North Korea shit again! Who cares if Kim and Trump are buddies!? Fucking good! As long as I don't have to watch people die! What does Biden even want!?"
"....Why do they talk about Russia whenever there's an election? I don't get it?"