While I do agree with the assessment that Nina was digging her own grave and alienating herself further with the whole "I'm deaf" thing, I think Jenn was being extremely insensitive.
Joe is a douchebag. Like a classic archetype douchey college kid. It showed in the literal essay he wrote in his bio, and it shows on screen. He reeks of trust fund baby who had everything handed to them and is very naive about how the world works and was given way too much self-esteem by the everyone-gets-a-trophy culture we have today. He thinks he's so brilliant but when it comes time for him to actually make and execute a plan, it's an epic ****fest, a la this episode's challenge.
Jenn isn't entirely wrong about being irritated by Nina, and Nina is ridiculous, but everything about Jenn, from her body language, to her facial expressions, to her word choices, to her interactions with Vince, to her confessionals, just screams "absolute C***"