Aram wasn't about to take any crap from the little, bald guy. At first, he was taken aback, but then he stood his ground and told Garvey exactly where to stick it in so many words.
Garvey is a pallbearer at Singleton's funeral, and Liz witnesses the whole thing. It's unbelievable that Singleton's murderer would have the gall to do that, but Garvey is a bastard and has no morals.
Red always has an agenda, and now it's clear he'll do anything to get those bones back. Yet, we still have no idea who the bones are, and why they are so important to Red.