It's deliberate obfuscation on the part of Meghan and other fauxbots - turn Castro's position of decriminalizing immigrants crossing illegally into "open borders." With the repeal of the federal law, there will still be consequences but not the family separations the government currently uses the existing law to justify.
Castro said, "We can maintain a secure border, and people are still subject to the law, but what I don't believe we should do is criminalize desperation.”
And Meghan completely distorts his words. Still. See her latest tweet