They don't enforce the laws they have on the books now, so what good will more laws do them? They all love it when the cops don't enforce marijuana laws, or push the homeless away from businesses and neighborhoods, per city laws, so what makes this special?
1. Hear, hear on your first point! The Parkland school shooting would not have happened if existing laws (Both gun laws, and laws relating to juvenile offenders) were actually enforced.
For instance, Nikolas Cruz was expelled from the school some months before the shooting. The school administrators were required by law to inform the police that he had been expelled. They did not do so. Had they done so, Cruz would not have been able to legally purchase a firearm because he wouldn't have passed the background check. Also, even though Cruz had committed MANY violent acts in the school before being expelled, the school administrators and deputies refused to ever arrest him for it, in order to comply with the Obama Administration's asinine school discipline policy, which among other things pressured schools to heavily cut down on student suspensions and youth arrests. Had they arrested Cruz for his violent acts, he again wouldn't have passed the background check and wouldn't have been able to legally purchase a firearm.
2. As for your second point, don't forget the DUmmies also love when the cops don't enforce immigration laws and refuse to cooperate with ICE, even when it comes to illegals who are known violent felons in need of deportation before they hurt anyone else.