Agreed, I am strongly for a VAT on all digital advertising revenue. Let's make ads more expensive so people have a real choice to pay or not. Plus, we can use the money to fund something that helps people.
Personalized ads are ultimately cheaper than non-targeted ads because you don't need to buy as many impressions to hit the audience that you're looking for.
As a rationale, consider the targeted tax difference the price of collecting, storing, and using radioactive personal data.
If Facebook had to pay a higher tax rate for targeted ad revenue, their priorities would start to shift.