I mean, no that's a strawman. Nobody believes "illegal immigration is okay". What liberals tend to believe is that illegal immigration is a fact of life, especially in the US where the border with Mexico is traditionally very porous, and there are two ways of handling it. One extreme - the current status quo - is to criminalize the event, build up border walls, spend billions of dollars hunting down illegals, separating families, using ICE to terrorize communities, and so on.
The liberal view is that these policies are counterproductive, similar to the drug war. It wastes money, disregards human rights, and treats a humanitarian problem as a criminal one. There are better ways of managing the problem of illegal immigration.
But if you don't criminalise it, how do you enforce it?
A lot of liberals do not want illegal immigrants to be deported. So, this is to say that if I book a two week holiday to America, I can immediately live there and work.
Because if the government then deports me, they are "violating my human rights".
No. Yes current conditions are inhumane, but illegal immigrants should be deported.