Amumu Ult interactions with smite

IF need be, I will record a clip of my instance with this frustration. We were getting baron, Amumu bandage tosses in and ults, then smites baron. A normal smite steal wouldve been fine but i couldnt smite whatsoever. MAYBE its a interaction with both chilling and skirmishers smite because that makes them damaging abilities.

WHAT ENTANGLED DOES: The target is unable to control movement or attack (rooted targets can still attack). This includes abilities and summoner spells that move the champion.

Smite shouldnt be stopped by entangled unless it's an interaction with chilling or skirmishers, since they are the only two smites that do damage to champions. Have not tried this with trackers so I'm not sure about that interaction but smiting an objective shouldnt be stopped by entangled, doesn't seem right for the description of the ability.

This ultimately gives Amumu a ton of more strength than I personally thought for when it comes to getting objectives and team fighting on those objectives.