The proggies don't care about the work-arounds.
They don't care that it will do nothing to stop gangs (who are one of their constituencies anyway).
They don't care about stopping the random spree shooter as they get to stand on the bodies and pontificate.
They just want something on the books to frighten people.
Charge stacking is a thing and the more charges that can be stacked the more control they have over a defendant. The more control they have, the more concessions they get.
It's all about legal blackmail.