Whoever told you that was a bad player and didn’t know what he was talking about. Sorry you had to get bad advice like that.
I don’t really care. That’s terrible advice and a Hulk in nullsec is fine. Rorquals have PANIC buttons that can save nearby Industrials, as well as remote reps. So either you were in a very bad “major corp” (lol) or that wasn’t a major corp and you just thought they were because you were new at the time.
Either way, Hulks are very commonplace in Nullsec and they mine so much with Rorqual boosts they almost always make the hull cost back within a day or two.