In Japan, any job is considered a lifetime employment. You are not supposed to quit your job. There is a sense of loyalty expected to your place of work.
In turn, it's also very difficult to get fired, since being not good enough is not a valid reason to fire someone. Hence why people like Gura can slack off for years and be fine.

That is to say, when someone calls a HoloJP a "traitor" for leaving, they're actually basing it on something very real in Japan.