Answer:
It has a negative connotation, suggesting a dangerous fanaticism.
Step-by-step explanation:
A rabid is one of the dangerous known creatures and does not have good reality sense and mostly makes random attacks. Therefore, MLK Jr. uses the word rabid in a negative connotation form to imply negativity. He says that he does not agree with the advocacy of evading the law or defying it; that is why he talks about the rabid segregation. According to him, people are committing serious offenses. Thus the use of rabid also shows the fanaticism can widely spread leading to the destruction.