There does seem to be a double standard, doesn’t there?No, actually there doesn't.
If someone has made a career out of saying bigoted things or associates with white supremacist groups, then they get a lot less slack when they get caught saying something racially offensive. And appropriately so.
Now as far as I know, Reid has not palled around with hate groups or made a habit of cracking black jokes or compiled a shitty voting record on civil rights, or suggested it would've been awesome of the US had elected a segregationist president.
So there's no double standard.