People coming to live in your area, not your personal home, to work hard for opportunities, are in no material way like pick pockets. Your analogy is so extreme I am tempted to assume you argue in bad faith. The economic success of the United States, its simultaneous growth and flexibility and prosperity is directly caused by our heightened skills to welcome immigrants and make use of their talents and desire for success (compared to other countries with similar demographics). We are awesome at welcoming people into a modern society that values smarts, individual diversity, getting along with neighbors of differing backgrounds, hard work, risk taking, striking out on your own, the NBA, good home cooked food, fast food, and Taylor Swift, and getting them to enjoy these things also.

It is to make a system where people are less incentivized to commit crimes.

This comparison is flawed because there is not legal pickpocketing, but there is legal immigration.

If there was a legal pickpocketing, and someone claimed to only be opposed to illegal pickpocketing, then it would be reasonable to point out that unless they're lying about their intent a solution to preventing illegal pickpocketing would be to make it all legal.

The analogy falls apart because nobody argues that they are "only" opposed to illegal pickpicketing.

If people are opposed to any form of immigration, then they should just admit that, rather than pretend they're only opposed to illegal immigration.