my understanding of the justification for a special system is that it's inherently more fragile and more tempting to attack than other government services, which generally provide tangibly vital, life-preserving services, rather than less tangible artistic and cultural ones, and the particular form of the service lends itself to being funded in a way that wouldn't work for other more vital services
healthcare is possibly one of the few that could (i.e. does in other Western countries) work similarly, but people including me would undoubtedly despise it. most things need some kind of mandated funding otherwise they would fail and people would die, go homeless, not have a military or live tangibly worse lives, and mandated taxed funding is generally better because it relies more on those with broader shoulders
overall I personally reject your notion that there's some kind of subversive justification for it
healthcare is possibly one of the few that could (i.e. does in other Western countries) work similarly, but people including me would undoubtedly despise it. most things need some kind of mandated funding otherwise they would fail and people would die, go homeless, not have a military or live tangibly worse lives, and mandated taxed funding is generally better because it relies more on those with broader shoulders
overall I personally reject your notion that there's some kind of subversive justification for it