The Visa Waiver Program was improved in 2015.
"Nationals of VWP countries who have traveled to or been present in Iran, Iraq, Libya, Somalia, Sudan, Syria, or Yemen on or after March 1, 2011 (with limited exceptions for travel for diplomatic or military purposes in the service of a VWP country)."
Just because it has been ignored by our previous administration, doesn't make entry lawful. It's far past time for enforcement agencies to follow legal mandates. Right or wrong, law is legislated. Instructing agencies not to follow laws created by legislature by defunding or other political means circumvents mandates created by legislature.
We are a democracy. If the law doesn't fit what the majority of the citizens want, change it. Effecting change without legislature is just wrong.