Because even though Tosen and Ichimaru betrayed the Soul Society, they still show them respect because they WERE captains at one point. More so, each of these men were fiercely respected by many When your a subordinate for a captain your very attached to them. Seeing as one spends alot of time together. They are highly respected and given alot of loyalty as well spending so much time with a person allows one to know them or assume to know them rather well.