Only according to a very, very few posters who just happen to be highly active on the buying/selling discussion boards, however overtime, whilst I am not such a prolific poster,  I have viewed numerous threads and posts from a far wider range of sellers on this topic who IMO would strongly disagree that they are doing a disservice to other sellers.

Well, they are doing a disservice to me. All my items are BIN (except for a couple). I have no opportunity to vet buyers pre-sale. A strike, however, benefits me as they can't buy.

They work, too. Had a 2000+ FB blocked the other month, so even high level of feedback doesn't guarantee they're not a NPB.