This may be a politicly incorrect thing to say and I’m not sure that the mods will let this up, but many people who are OTD are just as sure that being frum is wrong as you are that it is correct. The fact of the matter is there are no logical proofs that being frum is correct and the emotional benefits may not be apparent to somone who has not experienced them. Somone may also be of the opinion that they are not enough of a reason to be frum.
You have to respect and accept that not evreyone is going to agree with your opinion of unprovable things and that thinking less of them and pitying them for it is going to come across as arrogant and wrong.
PS. I do not want to debate so called “proofs” on YWN anymore then I have. Not because I can’t but because it is frustrating when your replys dont get posted or the threads get closed when you answer. If you want just research it and actualy read both sides of the arguments. In some cases you can simply google a proof i.e. kuzari proof followed by the word “refutation of”.