Because Leftists are now too damn cheap to pay for the cost of kidnapping and transporting slaves to the US so they do it under the guise of immigration.
Calling you a racist has always been a tool the left uses to shut down debate. They can't tell us why importing millions of people from cultures incompatible with our own is a good thing for America. They just call you racist and hope you'll shut up.
Illegal immigrants are still illegal. They are not the same group as legal immigrants. Every single country has the right to control who goes in and goes out of the country by definition. It's about following the law.