The planet money podcast recently talked about this. One of the reasons:
If you're "poor" and you spend 90% of your income on goods, you're getting taxed on 90% of your income.
If you're "rich", you spend 10% of your income on goods and just put the rest in other investments. This means that only 10% of your income gets taxed.
Still, VAT is a taxation scheme that actually makes some sense. Is it really hated? Why would it be hated?