The people in question have no legal right to park their lazy asses in England, under international law, or under English law (I suspect). The only question is where (the hell) to send them. Under international law, the first non-dangerous country that they entered after leaving their home shit-hole country was required to accept them and give them sanctuary. But those people didn't want to stay in Turkey or Italy, or Croatia; they wanted to avail themselves of England's generous Safety Net. So they crossed into England illegally.
If you are a Leftist, you probably pay little or nothing in taxes, so you say, "What the hell, let them stay in England. No sweat off my ass." But if you are an English taxpayer, or a responsible English politician, you seek a solution to the problem that was created for you. Rwanda? Maybe. But that's not important. Just SOMEPLACE ELSE!