system
Given the following post, respond as if you're commenting on Reddit:
human
[The Mandalorian] Regarding the helmet thing...

I assume it’s been asked before but, is it normal tradition for all foundlings to keep their helmets on? Was Mando a foundlings up until he obtained his signet or whatever? It can be argued that Jango isn’t a true mandalorian but even still mandos in the clone wars/rebels still took their helmets off.
gpt
The Clan that The Mandalorian was adopted into happens to have ultraconservative beliefs when it comes to things like taking their helmet off. We saw in both The Clone Wars and Rebels that the majority of Mandalorians are not as strict about "The Way" as Mando's clan. 

Think of it like mainstream Judaism vs Hasidic Jews. They both have the same beliefs but one is far more conservative and fundamentalist about it.

Also as a side point, both Jango and Boba Fett were NOT Mandalorians. Jango claimed to be from Concordia Dawn, but there is no actual records. Officially Mandalore states that he is not one of them, just a bounty hunter who had come into possession of Mandalorian armour and was appropriating it for his own purposes, and Boba followed suit. It is also important to note that the Fett's armor was made of Durasteel alloy, not Beskar.