1) Ah, so Halacha has no bearing on the question of entering the IDF ?
2) I assume you’re you referring to the Torah view on Divrei Rshus as ‘milei d’alma’. In which case you’re simply falling for the common error that “there is no pask in Hashkafa/Agadata”. In which case I withdraw from this conversation, because it will be pointless to try to hash that out here.
3) It is a modern invention that this applies to every saying of a Rov.
Nor did I say so. I said that the way I understood yichusdik’s post, I saw no room for such a mehalech.