"I'm unable or unwilling to read." would be more frank and straightforward than this summary.
It's due the reasons I covered in "all those made up arguments", as you call them.
What do you really expect to gain business-wise by publicizing a misguided personal grudge with a poorly written post? You don't mention you live in Taiwan. You don't even mention that you give discounts to non-US universities. So, in the end, you come out no better than those "other" companies. The post doesn't work as a publicity stunt either, as you make no mention of the product you're selling.
Why not opaquely offer e.g. a 10% discount to .edu emails and a %40 discount to less-"privileged" universities. No explanations needed, you just receive a discount code in your email address. No drama, no grudges, no need to write lengthy posts and argue with strangers on HN.
Disclosure: Never had a .edu email.
"Because I don't want to." would be more frank and straightforward than all those made up arguments.