Everything in this article is true. But the article itself is a big lie.
Trump was elected by votes of about half of Americans who are viciously against immigration in any shape or form. Now, he is doing exactly what his mandate is. By the way, he is strictly following the laws that those about half of anti-immigration oriented Americans managed to vote in before even Trump had been elected. The other half of Americans, did not protest when these laws had been voted in.
The real question, which the article cowardly avoids, is: “Why about half of Americans are so ferociously against immigrants?” They do, because for about a century they are systematically misinformed about immigration. What the major media outlets, as the Washington Post, did in order to countermeasure this misinformation? By the fact that this misinformation prevailed, it is obvious that the Washington Post, similarly as all other mainstream media outlets, did not do enough.
With the pen (probably it was a keyboard) of Greg Sargent, the Washington Post is writing how bad Trump is. If they were, they would be focusing on what they did wrong, or did not do at all, that made Trump elected. What they did wrong or missed to do that most of Americans are deeply misinformed about immigration.
My answer is: They did not have intellectual courage to publish texts as this one: https://medium.com/@hak1010/the-border-wall-is-not-the-real-problem-40864395de58