Because tweeting and complaining about immigration laws is far more effective than actually enforcing them and sending troops to the border, which should have been done on 01/21/2017.
Fly on the wall in the oval office hears:
"Daddy don't be cruel, let them in! They have babies and mothers!!"
"Okay honey. Whatever you say".
I bet if President does an EO and orders border closed, some leftist lawyer will find a leftist Judge and suspend it and tell the President he can’t do that. Our congress, with Repub majority could make the changes to the loopholes and fix the immigration swarm into our country. Former head of Ice today said there are loopholes that Congress can close but do not do so.
The PResident can only do so much with all the leftist Judges out there acting like they are the President. Repubs will not do anything this close to the election.