Because BlackBerry has some super special glass that no one else knows about or uses that doesn't scratch when you drop your phone from waist height... getting annoyed with the soft touch is one thing but using a scratched display caused by your own negligence as a reason to be disappointed in a phone is another. No offense but HTC didn't drop your phone nor did they say the glass is scratch proof. I've never had a bad scratch on any smartphone display and even though I'm extremely careful I usually put a screen protector on it for occasions exactly like yours.
Not trying to sound like a dick, but that's just dumb that you're contemplating moving to BB10 when it launches because your GLASS scratched which that BB10 handset will also do once you drop it from waist height without a protector.