It wasn't Freepers who said the guy looked "Hispanic or Middle Eastern" / dark-skinned caucasion, it was eye-witnesses. And speculating about al-Qaeda and allied jihadists isn't racist, it's based on: 1) We're at war with them; 2) They murder innocents; 3) They've launched a lot of attacks over the last 2 weeks or so.
And given the possibility (50/50?) of jihadist connection, it ain't racist to believe what we've heard about the shooter's (/shooters') appearance.
If the IRA blew up the WTC, and the witnesses said the sniper had red hair, would it be racist to believe them?