Can authors from certain origins really not know about the gravity of plagiarism?
I am not here to create or perpetuate stereotypes. I just want to make an attempt to explain it.

Yes, in my personal experience, in Asian countries, scholars fail to understand the basic concept of plagiarism. Let me give a background of myself, I finished my undergraduate in India and currently a graduate student in USA.

In almost every American University, there are clear rules imposed on assignments and laboratories. There are certain honor codes and honor committees which oversee the description and prevention of plagiarism. Plagiarism check software are utilized too. 

However, in India, howsoever unbelievable it is, there is no concept of weekly assignments in most (just a qualifier) of the Indian universities. At most, students are required to complete one (or two) assignment in a semester. The assignments also happens to be most boring ones. For example, "write report on recent trends in "Biomedical Instrumentation"". Unfortunately, even in those assignments, the grading patterns are usually (again, just a qualifier) binary, i.e. you get full credit if you submit the assignment and zero credits if you fail to do so. Thus, there is no mechanism to evaluate the thought process, the research skills and plagiarism related issues. 

However, the concern is, when even most of the professors fail to adhere to plagiarism rules. The reason being the professor evaluation schemes utilized in most (you know, it is a qualifier) of the universities. You are supposed to come up with these many conference papers and these many journal papers for doing fairly well in yearly evaluation. No emphasis on the quality of publications is established. To take advantages of such a sad situation, several conferences pop up from nowhere giving professors opportunity to meet the evaluation requirements. Some of these conferences are pathetic. How pathetic? You can submit a single page paper, for starter; You can submit paper as late as just a week before the conference. And what else is incredible, the conferences bear tags like "IEEE International Conference on _______ _______ and ______". Really? Yes, I know it's sad, but it's true.

These are what I believe the main reasons of why Indian scholars are so much at risk of plagiarism.