In part thanks to Trump's ridiculous plan to build a wall, the Left has wholeheartedly embraced the open-borders side of illegal immigration. I live in Chicago, and during the city's weekly protest, whether it's about reproductive rights or healthcare, there is always a contingent in the parade shouting "Hey hey! Hear hear! Immigrants are welcome here!"
Yet there seem to be many instances in which many who lean to the left would tend to oppose immigration, legal or illegal. For example, Israel. In the SJW crowd, there tends to be somewhat of a consensus that Jewish illegal immigration to Mandatory Palestine led to the appropriation of Palestinian land for an alien Jewish state. And if you believe that to be true, that's fine, but then it would be inconsistent then to oppose improved border security for the United States. Illegal immigration didn't work out for the Palestinians.
A popular political cartoon about the issue is some variant of the juxtaposition of a white American yelling at a latino immigrant for coming here illegally while a Native American points out how the same applies to the white American. And that's technically true--the Pilgrims certainly weren't vetted by Wampanoag customs officials--comparing European immigration to latino immigration is meaningless. If you want to express support for one wave of immigration, it doesn't help your case to vilify another.
Let's also not forget that in the early 1800s many Americans illegally immigrated to Texas and California, leading to their secession from Mexico. Or that even before that, Mexicans illegally immigrated to and claimed those lands from the native tribes. The Navajo and Apache certainly didn't--and still don't--consider themselves latino or Mexican.
I don't mind if someone is all for open border and unrestricted immigration. What just bugs me is that many tend to selectively choose which emigrations to support and oppose.