What would make an aggrieved party likely is that the church that makes allowances for “bi” is actually encouraging, at a minimum, a menage a trois.
The parents sued the church after the kid committed suicide. (I guess they figured if they had told the kid he would go to hell, that he wouldn't have gone ahead with the suicide.
IIRC the church prevailed, but I do believe the case went to trial.
If some counselor told some teenager that homosexual sex is not an abomination to the Lord and then he went ahead and did it and then got AIDS or Hepatitis C from the encounter, I think the same type of cause of action could be brought.