It’s obviously a tax on the biggest consumers.

Yes and no.

You’re absolutely correct in terms of total dollars contributed.

But the flip side is in terms of percentage of income. The wealthier you are, the more likely you are to have stocks, property and the like, which are usually exempt. So, as a total percentage of income, a VAT tends to hit the poor harder. (That being said, other taxes like capital gains are more progressive etc to make up the difference.)