Taxation is not theft.
Theft: "taking of another person's property ... with the intent to deprive the rightful owner of it." The INTENT of taxation is not to deprive the taxpayer, but to provide services that would be infeasible without said taxation. Whether it succeeds at that is debatable.
Scientific articles should be free.
Hiding them behind a paywall also reduces access to those WITH the necessary education to make use of them .
Society would be much better if currency didn't exist
The alternative is bartering. The goods produced by one individual may not be desirable by another, especially if the person produces an non-physical or specialty goods Bartering for high value items becomes difficult (e.g. I'll trade 3000 bread for your car is unlikely to work)