You specifically state that you have to use it upside down in clamshell to get any direct benefit from it performance wise.
Except he didn’t. He said
for optimal performance with this mod you have to “place the machine in a stand or flip it over on the table”.
He (assuming it’s a he) even included charts that showed there was an improvement to thermals, albeit much less (but not nothing), when using the laptop normally on a desk.
So I have to side with OP when he says you didn’t read or
understand his post about this
simple, cheap, and reversible mod that no one is forcing you to do.
It’s obvious that Apple didn’t increase or deliberately reduced contact with the bottom case cover in order to prevent the “gate” and lawsuits that would erupt when people burn themselves if this were the default config. But in certain use cases and with somebody who understands the risks, there’s no particular downside.
I for one never rest the laptop on my bare skin or even clothed skin because it can get a bit warm under high loads as it is without the mod, so I always put a sleeve cover in between as an insulating layer anyway, which I know would reduce the mod’s effectiveness when used on your lap but hardly makes it completely futile.