Taxation is not theft.

Theft is taking something without permission; tax has the implicit agreement of society.

Begging The Question

Agreement (consent) is the thing at issue, but by saying "tax has the implicit agreement of society" you are presuming consent exists, without evidence, in order to make your argument.

Taxation is not theft.

Taxes go towards stuff that benefits the taxee.

Fallacy Of Red Herring

The question of whether theft occurred hinges on consent to the exchange, not whatever the taxee may receive from government independently from being taxed.