Why did Thrall honor Orgrim and name the city Orgrimmar?
He committed genocide against innocent people and obviously it would offend the Alliance.
Bad idea if you're trying to keep peace and inspire your people to be peaceful.
I'm reading Cycle of Hatred and it strikes me weird that none of the orcs feel sorry for all the atrocity they've committed.
They just keep saying the humans held them prisoners and emphasize their pain.
Of course they would. The orcs tried to annihilate the human race, but they never acknowledge or admit that particular fact at all.
Two of the orcs' greatest values in life are honour, and strength. They are proud to be orcs, proud to have rid themselves of the fel magic and of Gul'Dan. Orgrim Doomhammer put them back on the road to returning to their former glory. I don't think he relished the idea of having to sack Stormwind but the humans had made it clear they wouldn't accept the orcs in their world. So they had to fight ruthlessly to carve out a space for themselves, and assert their strength to stop the humans waging war on them. Way I see it, orcs didn't have much of a choice - they had been seen as monsters from the day they set foot in Azeroth - mostly thanks to Gul'Dan. Humans have always been at war with them, killing them, then enslaving them - so orcs have always given the same back. No doubt there would be orcs like Orgrim who feel remorse about all the atrocities they've committed. But it's the orc way to be as they are and a lot of orcs would have wanted revenge for the loss of their loved ones and being forced into subservience.
Thrall might be trying for peace, but not at the cost of the orc peoples' very identity. Naming their city after Orgrim is kind of a statement, isn't it? We are orcs, we are proud of who we are and of Orgrim who helped to lead us there. We want peace, but we won't bow and scrape to humans to get it. We want peace, but also respect.
I read the books a long time ago, but that's my perspective on it.