I'm dying.
This isn't even going to help cause he's raging already, but chicks also don't want to make the situation more awkward than it already is. If you see this chick on a regular basis - work, school, whatever - the chances for a "yea maybe we can hang out sometime" are high. If you flat out turn a guy down, there's usually only a few outcomes, none of which are positive. You get the persistent dude who keeps trying to change your mind, or the rager who gets pissed, or the overcompensator who goes out of his way to show how he's doing better without you. Its full of awkward no matter the outcome.
It should be telling that girls encounter so many creepy dudes that they feel like they have to react this way to any guy they're not into. They're just praying a guy will forget about them and go onto the next chick so that they don't end up duct taped in a basement somewhere.