It is possible to walk and chew gum... Trump could have proposed an immigration reform plan to protect the dreamers, which is the moral and right thing to do, while also rescinding the EO to make the constitutional point. Or he could have let the EO get shut down by the courts and set a precedent on its constitutionality. This move was super careless, sloppy and divisive.
Quite the contrary, his move managed to unite Congressional Republicans and Democrats, both sides are falling all over themselves to get legislation going now.
They've only had FIVE YEARS to act on legislation but now it's an emergency that they care so much about? The DACA folks should be pissed off at Congress not Trump, Trump did the right thing for a change.