you know i just realized wu is an introvert.
we already know he's self critical to a fault and has a habit of pushing people away so they don't get hurt because of him, but i just realized that he's also probably not used to mass socialization.
he's spent thousands of years with it just being him, his brother, and their father. then their father died, leaving the two of them alone. then garmadon presumably moved out after marrying misako so wu was probably alone in the monastery for a lot longer than we thought.
he has all of maybe 3 living friends outside the ninja and garmadon. two of them were thought to be dead for YEARS, and the third is his brother's wife.
now he's around tons of people on a regular basis and i don't think he's quite used to that.
plus you also have his past experiences with other relationships to consider, which leads into his self-criticizing tendencies and probably his mentality of "i tried this and it ended badly so i'm not doing this again"
his ONE (1) canon attempt at a romantic relationship ended with his brother getting the girl first so he's never pursued a relationship afterwards as far as we know because if the one person he loved chose the evil brother over him then maybe he's the problem.
his ONE attempt at raising a child ended with the kid lashing out over ONE disagreement, leading said kid to running away and getting himself killed, so wu never took in kai and nya after their parents disappeared because he feared making them hate him and getting them killed too, because we ALL KNOW he blames himself for what happened to morro.
i mean, did wu ever actually KNOW for a fact morro was dead before lloyd got possessed? did he just assume the worst after he couldn't find morro again? how long had it been since morro left, even? the timeline's a bit murky but if wu met morro while garmadon was still studying under chen then morro would've happened BEFORE the serpentine war.
wu probably spent the last FORTY YEARS not knowing what became of the boy he cared for like a son, only to get confirmation in the WORST way that he'd been dead for a very, very long time.
and then you have morro's ultimate fate at the end of season 5. wu screaming his name while still reaching out for him as he dissolves still bothers me because that's still his son and he's lost him a second time.
where was i going with this, i had a point?
wu's not good with large groups of people because he's not used to being around them for long periods of time. and he's not good with kids because he's scared of messing up with them.
extremely sheltered upbringing + trying something new going very badly + strong self-blame = awkward old man with a fear of socialization
and now, in hdwgh, the monastery has like 20+ people living there now, and a good amount of them kids. wu has NO idea what to do in this situation.