I'm not understanding what you are trying to say in this paragraph. You are complaining about leaders who have dropped tummies, but then say you are not referring to men who are overweight.I have problems with leaders whose tummies are so dropped after years of being underused that they cannot stabilise their posture or balance readily. They wobble causing me to struggle to maintain my axis. I'm not referring to men who are overweight as this applies equally to men who are thin. It is a matter of physical condition and show dancers have that in spades.
FWIW, I am overweight, and don't feel it hurts me in social dancing. In fact one time a follower told me that she thought my weight might be helping my dance, as she said it seems to make me very stable, and she feels very safe to do moves with me that she doesn't normally do with other dancers (I think she was refering to single axis turns).