I don't agree with these 'ship them back' comments, at all. On the other hand there is a limit to how long a protest should be allowed to disrupt the city.
It's one thing to have a big protest march and shut down a major street for a few hours, it is quite another thing to shut it down for days on end. Whether it is natives, tamils, unions, anti-globalists, anti-poverty activists, or whoever else, a protest should not close down a major road for more than a day.
Even during that day I think the police should have moved sooner to open up a route for emergency vehicles. They could have reached a deal with protestors that only emergency vehicles would be let through so as not to lessen the impact of the protest.
As stupid as they are for waving the flag of a terrorist organization, and as much as it is likely just a fund-raiser for the LTTE, and as much as I think it's retarded that they are protesting at the US consulate, they do have a right to protest in public wherever they want and however they want--within reason.