take your number 2 option out.

it is your fault not reading contract carefully. it is not going to get you anywhere and apparently other parents have no issue with this clause.

Your last option "threaten to sue them" is hard to accomplish. So better handle it in a subtle way. Just say my kid seems to have many accidents here. could you help me to understand if there are some issues. and you can indicate this is one of the reason you want out.

pick your words carefully. you don't want to force them and yourself into corner and no space for spinning