How to respond to papers that put forward unreasonable criticisms of my research area? My research area (not me specifically) sometimes gets attacked by a handful of people who don't know what they're talking about. I don't have a problem with fair criticism, but these people are just being unprofessional.
To be more specific, the abstract of a critical paper might be something like:

We use technique X. After extensive testing we find that X is completely impractical. Moreover, X fails to do Y or Z. We conclude that X is a research dead end and the researchers working on X don't understand what they are doing.

A more accurate summary of the paper would be:

We implement A - one of many techniques from area X. A is widely known to be inferior to other techniques in the literature of X, but we are unaware of more sophisticated techniques. Some basic tests confirm A's inferiority.
 Due to failing to properly use A, it doesn't do Y. Moreover, A doesn't do impossible task Z. (No one claimed that A does Z.) We thereby demonstrate that we don't know what we are doing. 

How does such a paper get through peer review? Simple: They publish it in a different community, where no one understands X. Unfortunately, this terrible paper then becomes one of the most visible papers on X in that community.
Most people in my area completely ignore the criticism, although some do try to rebut it. As easy as it would be to ignore the critical papers and hope that others do too, the reality is that the misinformation they spread is harmful to my area.
I was wondering whether others have similar experience and can share what worked and what didn't. Can you win by arguing with an idiot/troll?
You can't change what is already published, so there is no point in trying to.

What you (and the people in your research area) can do is ask yourself why they used A instead of X. Maybe there is an easy-to-use free implementation of A, while it takes a PhD to really understand and implement X properly? In that case, you and your peers should fix the problem by releasing a tool to do X. Possibly an automated one, with a simple interface and no magic parameters to tune. Then you can recommend it to people in the other field.

Another thing you can do is collaborating with someone in that area, and publishing a benchmark paper where you test several algorithms and you show that X really works. A paper of this kind may be easier to publish in their area than in yours, where this fact is common knowledge.

If you simply call them idiots, you will never fix the problem. This is the wrong attitude; the blame can't be all on their side. You should borrow this principle from user interface research: if your users make mistakes frequently when interacting with your program/website, it is not their fault because they are idiots, but it is your fault because your interface is bad.