Most people can't. But then again most screamo is GOD-AWFUL!!!!
I hated Gallows viciously when I first heard them, but there is a lot LOT more to the GOOD examples than just a guy screaming.
Gallows and Ghost of a Thousand have fantastic musicians, and the song writing is actually creative and GOOD.
It might seem laughable to most people to even compare them to a band like Zeppelin, but as a long-time Zeppelin fan, these guys really are the only modern equivalent that have blown me away to the same degree.