Most of us foreigners are classed as tourists. You got yourself Thai citizenship, so now you have to pay Thai taxes. Everything comes at a price. Expats with 1 year extensions aren't Thai citizens, so how can they possibly be taxed as such? Only a fraction of Thais pay income tax, and an even smaller fraction of foreigners. The rest, vat, excise etc, everybody pays. So we contribute same as most Thais.