There are all kinds of price differences that have nothing to do with charity, and charity is not a requirement for price differences.

Don't pretend user agreements are the same as letting companies make laws. Everything you join, every financial deal you make, every contract you sign has terms and conditions. They all operate within the law of every territory they are available in.
If you believe regional pricing on digital goods violates the law, you are welcome to challenge it in court.

The analogy with student software is the same. Steam and GOG's regional pricing is not based on an individual means test, it is based on the region. You have to be Russian to buy the cheaper Russian keys, just like you have to be a student to get the cheaper student pricing.
The reason for the regional pricing is the difference in economies in different regions, but it can not be implemented on an individual level.

There are physical goods that can not be imported into certain regions, others that you need a special permit or licence for, etc. There are physical goods manufactured to only be sold in specified regions. Regional restriction existed for physical goods before there were digital goods.

If a digital distributor's terms of service are not acceptable, people are free not to use their service. Regional restrictions exist because regional prices exist because different economies exist.


similar restrictions of physical goods would never be accepted?

Really? Then why were there regional pricing for physical games long before digital distributors existed?


Wait... 'obviously'? Why obviously?

Because it is blatantly obvious.
Add regional pricing, but no restrictions. Which price would most people pick? Can game companies survive with that business model? If you significantly cut the revenue of every game company, what would that do for their next projects? How many game publishers would put out retail releases knowing they would have to compete with the digital versions at a fraction of the price?

Objectively, what exactly do you think would happen to the game industry as a whole without regional restrictions? Do you think regional pricing could survive? Would it be better for the game industry if there were a single price, and poorer regions went back to piracy predominantly rather than being a significant portion of the market?