There seems to be some misunderstanding or confusion here.

Rating (sending feedback to) people who are unlikely to scam (positive) or high-risk (negative) is the primary use of the trust system and directly related to doing business here. Nothing that LoyceV said hinders that.

Including or excluding users in your trust list is different. You need to weigh whether the person's use of the trust system will have value to other users (at least to you and those who include you, or to the default trust system if you're in DT1). This isn't directly related to business, other than perhaps asking yourself "would this person's sent trust ratings and trust inclusions/exclusions be useful or harmful to other users trying to do business here".

It literally says so at the top of your trust list (emphasis mine): "List the users who you trust to have good trust ratings and good trust lists, one user per line. Prefix a user's name with a tilde (~) if you want to exclude them from your trust network."

Seems quite straightforward. Don't overcomplicate it.