Justified...and this chapter finally confirmed it.
First of all it is good to denote Tobirama's personality: He is straight forward, blunt, and he doesn't sugar coat what he says. So clearly he distrusts the Uchiha, and because of his personality he comes of as kind of an ass.
We also have to establish his views on the Uchiha in order to respect just how much he actually did for them.
Tobirama clearly disliked the Uchiha...saying he hated them is honestly an arguable possibility. But why shouldn't he?! He grew up constantly killing, and having his friends and family killed by them. Finally, they decided to make peace....and then what happens? The leader of the enemy clan, that they were finally trying to get over their hatred and losses, decides to fight his brother in what at the time was a fight to the death. I have a brother (honestly any sibling would do) so I can personally say that if someone tries to kill him...it isn't something you would tolerate. Despite this he understood the problem that the Uchiha faced, and found a solution for it. He explained that the Uchiha's power comes from basically heart break, and this leads them to go basically crazy with anger and power. This shows that even though he hated his enemy, he understood them as well as respected them (telling Orochimaru he doesn't understand Madara).
Despite his mistrust of the Uchiha, and the risk they could pose with the prospect of heart break he still did what he did.
By establishing the Konoha Police Force he did 3 things:
1. Gave the Uchiha clan an important role to partake in for the village's sake.
2. Gave the Uchiha a way to utilize their broken hearts and power to keep criminals from harming the village as well as to keep them from losing themselves in madness by being able to exercise their power.
3. Kept Konoha save (having the Police standing right by the prision...not only police, but VERY STRONG police to catch any escaped prisoners or handle a riot).
By giving them this role he also could have tried to make those in the clan who didn't secretly support Madara realize and try to convince those who did that their was no reason to go against Konoha...because instead of a rivalry they now had a family home of a village to defend. This same concept explains why Kagami or whatever the name of the Uchiha that was in Tobirama's squad during his final moments was even in the squad. Despite not liking Uchiha, Tobirama still tried to involve them in Konoha. He even sacrificed himself trusting that the next generation (including the Uchiha) would defend Konoha.
Tobirama's actions seem very just (though we still don't know what is up with Edo Tensei...), but the problem is that his personality makes it seem like he is just being a completely distrusting douchebag....and this is exactly what the Uchiha who supported Madara thought. They thought Tobirama was just being a prick.
