This can be spun both ways, that I agree. Although I did say that books should be cheaper, I agree with you in the fact that producing a good textbook is expensive (in more ways than just money) and time-consuming, and they should be valued accordingly.
I do believe, however, that it is more valuable for us as a society to have this sort of knowledge-disseminating piracy, than to strongly enforce textbook copyrights. You can argue that without the monetary reward, no good books would be written in the first place, but I disagree, I don't believe that most people who write textbooks do it for the money.
The point that those students are spending much more money elsewhere is moot. Textbooks are obviously not a basic necessity. Should a student sacrifice two month of his social life for the sake of purchasing a new textbook? Which of them will benefit him the most throughout his life? What is worth more that a textbook, and what is worth less?
This is all relative, of course. You say that anyone can ask for funding to buy textbooks. Where? In America? Me, I'm studying in Portugal, so I'll speak of what I know. We have good universities here, but there are no funds for buying books, and the 3-5 copies in the library are hardly enough for the dozens of students who procure them every year.