How should I consider a possibly rude reply from a potential PhD advisor?
He/she is probably very busy, and has repeated the same message probably N times.  Also, we all assume students will find the required information by themselves.  Nowadays, I find that students simply don't spend the time to look for information.  Their first instinct is to simply to message me, and hope that I will solve their problems for them; this is very similar to a kid asking their parents, can you please clean up after me? It is ok if you are 2 year old, but not OK after a certain age.
As for whether the professor should be a supervisor, you should look at whether he/she is successful in supervising students.  Yes, he/she may not entertain trivial questions and tell you off, but that may mean you need to work independently and at a high level.