Yuri also likes Matt! He knows some Zenites he considers decent people and collaborates with, so he's not hardline about factions in that way. Anyone he spots targeting civilians or sowing chaos he'd gun for, but that's not Matt.

If he spots Matt helping civilians, he'd give him a hand with that. Seems to him the guy's heart is in the right place, so I could see Yuri wanting to make sure no one gives him trouble when he's just doing the decent thing.