It is morally right, and it's not theft.
The government gave you roads, police, health care, safety, education and etc. If you're an entrepreneur you need the working government and the rule of law even more, and you also use people (labor) to increase your prosperity. You are delusional if you think that you don't owe anything back.
You don't earn much money? Ok, in most of the countries you don't even need to pay taxes if you're poor. But if you're prosperous enough, be kind to pay your debt back.
You don't want to pay it? Great, you can leave and choose any country with lesser taxes like some banana states in Caribean Sea, in some of them there are no taxes at all, but don't whine that there are no infrastructure and qualitative services as well.
So if you want to live in a prosperous country, taxes are not theft, it's your payment for good life and opportunities. Resources are not limitless, and if you don't pay your fair share, you basically deprive something from other people. So taxes are not theft, but NOT PAYING TAXES is theft.