There is a real conflict here. People are getting loans for their education. A loan is an investment, and should only be taken if it will pay off.

If you are getting education because you are interested in the topic but won't get a job in it: I fully support this. However you should not take a loan out to get this education: there are too many other things to do in life that you also will want to do. Worse the loan means you cannot change your mind later if you are wrong (or you can, but you will still have to pay for the mistake instead of whatever you are interested in today).

There is one other reason for education: to become a better citizen (don't fall for bad politics). However that should be to everybody and I haven't seen much evidence that higher education really helps much.

> People are getting loans for their education

In some countries they do, in some they don't, in others every PhD student even gets a scholarship. Every person I know who did the PhD did it because they loved the topics they were studying. The author of the blogpost is from Russia, I bet he didn't have to pay for his PhD.

While it would be insane to get a PhD if you had to pay for it, at least in the US you are paid a stipend (if not a good one) so you can generally avoid any debt. There is definitely an opportunity cost though.

It's very rare and extremely un-recommended to get a loan for a PhD. For most people, at worst, you're losing money by opportunity cost.