It's not ironic, it's basic math. Based on just the amount the post said he gained, the campaign funding is 1% of what he'd be paying in the tax, even less because that's not his entire net worth.

That's the math you have to consider with all of these counter-campaigns - the money they're spending will always be less than what they expect to pay, otherwise they'd just pay the tax. That's always the driving force, regardless of what their smear campaigns say.