I won't repeat the spirit messages I received that depicted ACIM in a negative way, because apparently, they weren't taken seriously by others (why should other people take my messages seriously, perhaps I was dealing with new age imagination
).
Whatever the case, I believe that "anything" that causes a person to be brainwashed and take on a cult like mentality isn't a good thing. There seems to be some people who get so involved with ACIM, they have a hard time seeing beyond it, and on some occasions don't look for other means of growth.
The course is certainly set up so it can have a brainwashing effect, considering how the text has you read the same few principles over and over and over again, has a 365 day affirmation course, and states things such as it is required and can't be questioned.
Regarding how it speaks of evil, it can lead a person to believe that there are no evil minded beings to contend with. Warren Smith and his wife were involved with an ACIM reading group. He and his wife started to have problems with negative influences. When they spoke to their ACIM reading group about these experiences, the group wouldn't believe the Smiths were dealing with something negative. Their minds had been programmed to believe that such a thing isn't possible.