A Center Controller reported an aircraft deviated for weather from their assigned heading and flew below the Minimum Vectoring Altitude.

Narrative

I was monitoring a Controller. Aircraft X was west of ZZZ1 and direct ZZZZZ expecting RNAV XXL at ZZZ. Controller assigned 2;300 ft. and heading 160 with precipitation in the area. Shortly after; Controller stated that Aircraft X was below the 2;900 ft. MVA surrounding ZZZ1. He assigned Aircraft X a climb to 2;900 ft. Controller seemed to believe that Aircraft X had deviated around weather after being assigned the 160 heading. I did not hear Controller approve such deviations; but it's possible he did so. Suggestion: The obvious solution is don't bust the MVA. However; I have noticed that some controllers immediately descend all aircraft to the lowest available altitude; usually 2;300 ft. Aircraft X had 40 or so miles to fly and would have been perfectly fine at 3;000 ft. or 4;000 ft. Perhaps encourage facility controllers to not be in such a rush to descend aircraft all the way. Explain to people that it's perfectly possible to conduct a stabilized approach without dumping to below 3;000 ft. 50 miles from the runway.