Can poison action card destroy Warbot?
No, it can't destroy Warbot, but that's because it can't destroy minions in general. It can only destroy actions attached to a minion, and Warbot doesn't prevent that.

Poison affects Warbot as any other minion because Warbot's ability has no effect on Poison's ability.


Poison doesn't destroy minions.
Warbot's ability doesn't prevent actions from being played.
Warbot's ability doesn't prevent actions attached to the Warbot from being destroyed.
Warbot's ability doesn't prevent the Warbot's power from being reduced.