A distinction that works against your point is that we don't vote on monks, we vote on nodes. Monks don't have reputation, nodes do.

I understand that the reputation of my nodes is tied to my xp, but when I vote, I'm voting on the node, not the monk. There are poorly thought out replies in PMD just as there are technically inadequate answers in SoPW and I would still want to have the option of downvoting them. Also, upvoting or downvoting nodes by Anonymous Monk are still useful, as the good nodes get highlighted to the community and the bad nodes pointed out as well; this despite the fact that it has no impact on anyone's xp.

I certainly take your point that nodes should not be downvoted simply because of opposition to the opinion expressed. In my utopia this is accomplished by a culture of kindheartedness and lots of documentation rather than taking away the mechanism altogether or starting a flame war.