What do you do when you've promised to massively cut taxes, but even after you cut every service you can, the budget won't balance? You charge user fees!
What do you do when you've promised not to raise taxes, but the budget was left unbalanced by your predecessor and you have spending promises to fulfill? You charge user fees!
No-one is making the case that user fees are better than income and sales taxes. It is just a lot more politically convenient.
As much as I want to blame the politicians on this one, it is also the public's fault. TANSTAAFL!