Let me put things into a simple POV: Do you enjoy driving on the road? If you are in America you are likely to say no because the roads are quite bad, but if you are European you wouldn't be negative about the roads. (this is at least in most instances)
If it wasn't because of Tax, you would enjoy driving much much MUCH less, because you would be driving in the middle of nowhere, on a dirt road. Don't forget the government pays for the infrastructure that we all use every day. Now... Do we pay more than needed? That is a whole complete other question. But to answer your question, I think it is not theft.
If the government did not have a monopoly on the roads...just imagine how much better they would be today.
There was a government monopoly on telephones for 50 years from 1934 to 1984. Think of the advances in telephones during that time, and think of the advances after.
We should be driving on smart roads right now. Or not on roads. Government fucked up roads.
Same thing with railways. Most of railroads in the US we private which let the industry and infrastructure grow with amazing speed. The natural monopolies don't really exist.