Cook, et al.'s study is well designed and well executed.  The methodology is described, as well as are the bases for all conclusions.  Reservations are presented.  

Friedman, the critic you cite, is free to conduct his own meta-analysis of the literature and his own surveys of experts.  Instead of doing this, he tries to pick at flaws in Cook's study.  

Wow!  You mean a study has flaws? 

However, all studies have flaws, which is why we use meta-analyses.  Read here for the results of other studies similar to Cook, et al.:

https://en.wikipedia.org/wiki/Surveys_of_scientists%27_views_on_climate_change

About the only study that does not support Cook et al., was a survey of people who worked for the petroleum industry.  

Your guy Friedman is a lazy "pseudo-scientist."  He has done nothing original, nothing that requires the hard work of a climate scientist, and nothing where he can make an argument based upon data. 

That's the quality of arguments you get by climate change deniers.