I don't see how it's fair of you to encourage others to downvote a comment. If people agree with you on the evaluation of this comment, they will vote accordingly. If not, not.

By explicitly requesting downvotes, you are encouraging people that would not have taken this decision otherwise to downvote, circumventing the normal thought process. The Karma system allows each user one up/downvote per item, and you're supposed to up/downvote if you personally consider something worthwhile or not. By encouraging others to downvote, you are converting personal influence into a multi-downvote right for yourself.

You might of course believe that you, as founder and admin, represent the true volition of LessWrong, which is fair enough. You already are the judge of what gets promoted to the front page, which I don't have a problem with, as it is clearly stated. But in that case, you might as well directly access the database and bring the downvote level to what you'd like it to be. By inducing a downvote mob, turning the community against certain users, you are corroding community spirit. What you just did is analogous to the popular kid saying to another "Go away, we don't like you. Right everybody?". Again, if you don't want certain users here, as you have indicated with timtyler, you are free to ban them outright. But if you don't want to assert such a right, then you shouldn't be doing it indirectly either. This is dealing with the problem at the wrong level of abstraction.

This community has been built around your writings and contains a large amount of people who take your opinion as authority. I urge you to refrain from using this power as a community management tool.