where newbies will find it and be misled or driven away from Perl.

And that rightly justifies the replies. However, downvoting still achieves nothing. And, lest we forget my original comment "If you didn't read it, why both vote and reply to it?", which has zero to do with preventing new users from anything about Perl.

You just argued that downvoting his posts is tantamount to "suppressing" people, but you'd support outright banning him?

I made no such comment! I was responding to the idea that "If multiple people who used to be reluctant to downvote at all are becoming quick with the trigger, maybe that shows the extent of the problem" is an intolerant approach. Nothing against the downvotes themselves.

a better solution

There are many (better) solutions. It depends on what flavor people want. Here's some that might require tweaking:

1. Defaulting Note Ordering in User Settings to "Best First"
2. Show post reputation
3. Allow comment filtration based on reputation
4. Allow an "answer" or "seconded" flag for replies.

#1 is used by some other popular sites. bad comments aren't hidden. Good comments simply take precedence.

#2 is said to be open to abuse. However, hiding reputation is also open to abuse.

#3 is used by Slashdot. Anyone can see what they want. They can change the default to anything they want. But, a default is applied simply to filter out the worst comments.

#4 is not rep. It would be a simple way for people to vote on the current reply. Perhaps limited to one per question. It doesn't say "nice post." It says "this is the solution."

Positive reinforcement usually works best. That is, no action against abusers, but without support, they are all but consigned to oblivion.

The other approach is optional and default filters. Those are good to help newbies until they learn the ropes.