The pilots busted their approach clearance. ATC could certainly have rescinded their landing clearance and ordered a go-around. That said, ATC's responsibility

The pilots busted their approach clearance. ATC could certainly have rescinded their landing clearance and ordered a go-around. That said, ATC's responsibility is to keep planes from hitting each other and maintain an orderly flow of aircraft. They are not any way responsible for the safety of the flight. That is what the second pilot and all of the automated alarms are for. The crew just ignored all of them. It takes a basic standard of professionalism to fly a jet airliner, and unfortunately neither of the crew members on this flight had it. The approach was so bad that they were above the maximum gear extension speed when they tried to put the gear down, and so the Airbus refused to do it, and continuously yelled at them that it was doing this, but somehow they failed to notice. Monitoring airspeed on approach is about the most basic thing a pilot does, and if you're off on speed and/or altitude by much less than these guys were, the absolutely clear requirement is to go around and try again (before you slam the engines on the ground and destroy them).