How is it that smoking does not nullify ablution (wudu), despite its being religiously forbidden based on fatwas from the Permanent Committee for Scholarly Research and Ifta in the Kingdom of Saudi Arabia, Sheikh Muhammad ibn Salih al-Uthaymeen, and the Egyptian Dar al-Ifta?

Smoking is forbidden because of the harms it entails and the waste of money. Its prohibition does not mean that it invalidates ablution (wudu’). The acts that invalidate ablution are specifically defined by religious law, and there is no necessary connection between something being forbidden and it invalidating ablution.