By that kind of reasoning what purchased goods or services I get from any entity wealthier than me aren't a regressive tax? For instance I bought a sandwich from Subway yesterday rather than making one at home, because it was more convenient. Was that a regressive tax on my food?
Imagine there is a drought and the price of food rises, because food is scarce. A few people can no longer afford the whole sandwich.
To pander to those who can no longer buy the whole sandwich, and take advantage of the drought, those well off start buying even more food, more than they need, and reselling the sandwich, per-bite, with huge markup. This also drives the price even higher, due both to the markup and to the increased demand from the resellers. Now even less people can afford the full sandwich.
The resellers parasitic per-bite markup is the regressive tax, not the sale of the sandwich. The markup transfers wealth from those without the ability to buy the whole sandwich to those who can resell, when reselling is providing no value. Everyone was able to buy sandwiches just fine, before the drought. Those buying per-bite are also now going hungry, most meals, because they can only afford a few bites.
The solution is either to find ways to end the drought, ration the available full sandwiches, or sell smaller sandwiches, not to allow drought-profiteering that exacerbates the sandwich scarcity and makes more people go hungry.
