Sure, but you could say the same thing for teachers, foodservice workers, nurses, etc.... yet they are unable to avail of this program, for reasons I don't understand.
These are mostly employed positions, where employees have procedures to negotiate their salary with the employer (which might be the government itself).
Most artists otoh are self-employed, and the government decided that the country at large would benefit from giving some of them economic support. You can argue with the modalities but the reasoning does not seem that opaque to me.