They certainly can, but only with a court order.
And in order to get that court order, you have to legally file an eviction notice, which the squatters can appeal.
Only after all their appeals are exhausted, which can take months, can that court order be handed down.
How can these 2 have rights as tenants when they are not paying any money. Could I just go to my neighbors house and say I am not leaving and just live there?