It's a matter of leverage, though it's probably negligible. It's not that hard to bunny hop a bike with drops from the tops or hoods, possible more tricky if you're actually in the drops at the time...

Spending a bunch of my youth on a BMX, it is a skill I can pull out of my back pocket should the need arise, but if I encountered that kind of thing in my commute so often that I had to consider my choice of handlebar based on the need to bunny hop?...I'd find a different route to work.