I think there were a few reasons that Cameron didn't work.
Firstly, his dancing just wasn't up to the same standard as the other pros and he always seems out of sync. That had to raise question marks as to how he'd handle a celeb who didn't know anything about dancing.
Secondly, as others have said - a lack of social media engagement and not appearing on tours. If you're a benched pro looking for a promotion to main pro, utilising social media and getting yourself known to fans on tours are the best ways to do it.
Thirdly, he didn't fit any specific role on the show. I'd say there's four types of male pro that the show has generally stuck to - the foreign hunks (Gorka, Giovanni, Vito, Aljaž, Pasha, Artem etc), the 'homeboy' (Kai, Kevin, Darren Bennett), the pretty guy who appeals to younger viewers and dances with younger celebs (AJ, Nikita, Carlos) and then there's usually a big personality in there (for years, this was Brendan & Anton, now Johannes & Neil). Like it or not, this is a formula they've stuck to over the years and all of the successful ones have fit one of these types.
I feel genuinely sorry for him, he is very young and being so far away from home and possibly having a very negative experience can't have been a fun time. I wish him all the best and hope he finds a gig that suits him well.