Sure, some people have good reasons for not using the flat bench. I don't know if decline should be considered "safer" since that has issues too. There have been instances with people passing out from blood rushing to their head.
I don't think it's wise to give lifting advice from one subjective experience. I think you gave bad advice. Maybe you went too heavy? Maybe you had piss poor form? Maybe you didn't warm up properly? But whatever, this isn't a lifting forum so I doubt people are looking for advice in this thread.
Also, everyone is different (needless to say).
But Ill never get to 400 lbs on benching. Lol, unless, maybe, I take roids. I can deadlift that easy though.
Go Bills!