I don't know that anyone supports "illegal" immigration. I think too many people don't understand the complexities of it and how broad the topic is. For example, crossing the border anywhere to seek asylum is legal. But, most migrants don't fully understand the requirements which is why so many get turned away.

Aside from the humanitarian component, there's also a huge positive economic aspect to immigration as well. For example, in Texas, we all know how much our economy relies on migrant labor so we don't have these freakouts about migrants. We also know that border communities are some of the safest in the country.

There are more reasons why people support immigration. The downsides to immigration are far fewer than many would have us believe.

I hope this answers your questions.