They are definitely homer, but it's a different brand of homer than the sort of homer that pisses me off.
It's completely non-malicious and more tongue in cheek and done in humour.
EG Spurs announcer homerism: I really hope Aldridge misses this shot, oh damn he made it, again, lolz he's killing us tonight we just can't stop him
EG Kings announcer homerism: Isiah Thomas is a better point guard than Tony Parker.
There's a massive difference - you can especially see it when talking about bad ref calls
EG of when the call goes against the team
Spurs: that's a bad call
Kings: that's a bad call
EG of when the bad call is in favour of the announcer's team
Spurs: 'Wow, we really caught a break there because I think Timmy fouled / Parker stepped out of bounds, but I'm not going to argue with it lolz GO SPURS'
Kings: that's good officiating. good call by the ref.
etc etc