True, but, legally, one must go through quite a process, there are caps on the numbers of legal immigrants from many countries, and, most important, Trump's paper clearly very heavily reduces the incentives to come in. It's sort of like an employer saying to a hord of job applicants "Sure, you're welcome to apply, and here's the 40 page form", but unsaid is the fact that there are only 2 positions open, and with very demanding / specific requirements.
Back in 2008-2009, I got that as a job applicant a LOT. :-(
Trump has said numerous times that he would "expedite" them back. He has never said that they should go to the back of the quota line and wait up to 10 years which would be the normal amount of time.