$100/week is pretty damn low if you ask me.
Make it 4 weeks and it becomes $400 a week. Spam the forum with shitpost, and $400 is easy. It seems low to you since you are in a campaign which is paying up to $300 a week but when the forum average signature campaigns are paying even $50 a week, $100 a week seems very decent to me.
Why it's not good practice? Red tag will stop them from joining other campaigns in future and maybe they will think twice before starting to promote 1xbit.
Feedback positive and negative are only good use case when you are doing a trade with other party. It used to be leaving feedback for anything even for a statement you do not like but since theymos added flag system and updated the concept of new feedback system back two years ago (more or less) the perception has changed.