Nitpick: Scott didn't coin "weak man", he mentioned it because the term appeared in the fallacy/bias literature. Previous to that on Scott's blog, I coined the term "flesh man"; later someone proposed "tin man". I don't know why Scott didn't use my term :( , or "tin man", either of which is much better.

A flesh/tin man is an argument/position that a real person actually holds, but where this real person has been selected to represent the worst of whatever side/camp you want to tar with the brush of foolishness or nastiness.