No, it's not. They did it before PEDs, and they'll do it after. They're brutal yes, but that's what makes them legendary. And for the pros, it's not like they're getting killed just by doing one per season - quite a few pros use one pro multiday event to prepare/peak for the TdF. So no, it's not 'too hard' for the pros.
Yes, it's wayyyyy too hard for us amateurs, but that's why we're also not famous.
I do agree with some of the pro complaints in the past that some prior courses were too dangerous/technical, and that made it too risky to ride aggressively due to the risk of death (not just crashing, but death from falls of a cliff etc.) Technical courses are fine, but shouldn't result in death if you make a mistake.