In my experience, you find all kinds of people. There are people who do not tolerate any type of criticism, but it is not common.
If your criticism was constructive, that is, without insulting or belittling his work and he still blocked you, he is really the problem.
The Internet is a public place, full of very different people. Don't worry, because you made your comment in good faith.
Sooner or later you are going to run into another person like him, who will see any criticism as an attack and there is nothing you can do, however, this is not normal. Most people tend to accept or at least not react to criticism unless, of course, it is written in bad faith.
It is difficult to find an explanation, sometimes the other person is going through a bad time and takes a simple comment in the wrong way. Other people really have problems and can't tolerate dealing with criticism, etc.