Your position is illogical. The question "can this person do the job" can be a resounding, objective "yes", for someone who, say, also happens to embezzle cash from the company. If that's the "only thing that matters", then the thief should keep the job and continue stealing.

Especially if you want to defend some unpopular position, you have make sure you don't have logical holes in it, like universal absolutes that succumb to easy counterexamples.

No. Can the person do the job includes their obvious drawbacks ( like tendency to steal ). I do not consider writing a book, however salacious and 'wrong' it may be, to be in that particular category.

The guy is an asshole, but it is hard to argue he does not know what he is doing.

If he wrote a book on how to embezzle from companies, would that be 'wrong' enough for you?

Do you realize that the Civil Rights Act is also a law that companies have an interest in their employees not breaking?

The guy seems clueless how he affects people he manage, so is unfit for the job.

He sounds like a 0.1x employee.