If you don't have the power to change something, griping about it is like getting upset at a rock you stub your toe on. A natural reaction, perhaps, but in no way useful. The only effect of such a reaction is to make life unpleasant for the people around you. I do this a lot, so I know.
If you do have the power to change something, griping about it is like pointing at a pile of dog poop on the sidewalk and loudly saying "someone ought to clean that up." You are someone. Why don't you clean it up? I do this a lot too. It's really useless. It humbles me to see people who actually clean up the dog poop instead of complaining about it, and to the best of my limited ability I try to emulate them. I feel best about myself when I succeed.
So what about the bumper sticker? It's a truism that government takes money, in the form of taxes, and that some amount of that money is wasted. It's not unreasonable to describe this as stealing. But it's useless to speak in generalities, because it means that you are griping about something you can't change. It will always be the case that there is government waste of tax money. If you think it can be stopped, you're delusional.
Take away the government, and a new one will form to fill the power vacuum. It will also levy taxes, and it will also waste some of them. Take away the government's ability to tax, and it will fail, lacking the money to pay for its operation. A new government will arise to fill the power vacuum. Don't be naive enough to think that the new government can only be better than the old one. Maybe it will, maybe it won't. If you actually want change, work to change what you have into what you want. Don't just blow everything up and hope something better arises through random chance.
So when you phrase a complaint in such a general way, you might as well be complaining about the rock you stubbed your toe on. You can't change the fact that government is imperfect. If you really think that government waste is a bad thing, identify some, and work to put an end to it. Pick a problem you actually have a chance of solving.
And if you just want to have a clever bumper sticker that makes you look smart, take a hint from someone who knows: griping doesn't make you look smart. It makes you look like an ass.