The thing with Obito is, I didn't buy Rin being his trigger.
Oro's trigger being his parents was only implied not confirmed but yeah they're his damn parents, no shit that would change him. Nagato, Konan, and Yahiko were shown to be best of friends, Nagato was also portrayed as weak-willed and easily coerced from the start, I can buy his trigger. Sasuke lost his family and clan who he loved so much, yeah I can buy him being crazy. Same with Madara and Izuna and so on and so on.
Rin and Obito suffer from similar problems as Sasuke and Naruto, I don't buy it that their relationship was so damn close that Rin dying could break a strong willed character like Obito so utterly. The only thing we saw of them was a sweet young friendship and schoolboy crush that wasn't reciprocated.
Now if Obito was portrayed as having some unhealthy obession with Rin(him kissing her photo would've been a good way to start dwn that path) then I would've bought it. As it stands I don't feel Rin being his trigger was earned in the same way I don't feel Sasuke and Naruto's relationship as portrayed in this chapter was earned.
Also Obito looks he just flipped a switch, he never seemed to struggle with his new path after Rin died, it's like he just went full on baby-killing mode, he really really needed to be fleshed out.