skyjedi2005 said:

In Season 2 via the bonus material Filoni explains that Boba Fett and Jango fett are just random bounty hunters and not Mandalorians anymore.

George Lucas decision

Yes, they were never born Mandalorian.

skyjedi2005 said:

Karen Traviss was right they completely destroyed the mythology built up carefully over thirty years plus in the EU.

Karen Traviss was wrong. She was the one who destroyed their mythology by "turning them into a bunch of Boba Fett's" as Filoni puts it. Which is true.

And the whambulance is getting tiresome.