//Calling them illegals is like calling anyone accused of a crime of being guilty before they have been tried.//
They have arrived without leave to do so, which is illegal (try arriving in Paris CDG having chucked your passport down the kharzi en route). They would be entitled to protection under the UN Convention on the treatment of refugees if they arrive directly from a country where they were in danger. But they don't. So they are illegal immigrants and describing them as such is perfectly appropriate. The problem is, instead of treating them as such, they are provided with accommodation, food, drink, healthcare, and pocket money.