The name "evil spirit sect" was enough to tell that this sect wasn't a good one. It was definitely a devil cultivation sect. These devil cultivation sects weren't afraid of killing people. They might have done things like exterminating the human world before. To them, the people in the spirit weapon world were like pigs and sheep that they raised in their pens. They needed these pigs and sheep to kill each other. Once they gave out the words that these pigs and sheep didn't kill each other but instead United and wanted to resist them, they wouldn't be polite. They would definitely deal with them and clean them up.
Some people might say that the evil spirit sect was not the only sect in the world where the evil spirit sect was located. They were a sect of the devil cultivators. Could it be that there were no righteous sects to control them? could it be that the righteous sects did not care about them killing the innocent?