This 1922 article by Big Bill Haywood is of interest if the historical context is taken into account.
Current Phases of the Class Struggle in the US
It criticises the AFL for running "closed shops" but really meaning "closed unions". But at the same time the IWW's broad based industrial unionism was certainly not "open shop". Perhaps its a non-question. The real question is whether unions should be prepared to clamp down on employers who pay non-union rates.
Edit to add: One thing that I do reject, though, is the idea that closed shop is a "bad thing" because it is coercive. This is something in its favour.
Current Phases of the Class Struggle in the US
It criticises the AFL for running "closed shops" but really meaning "closed unions". But at the same time the IWW's broad based industrial unionism was certainly not "open shop". Perhaps its a non-question. The real question is whether unions should be prepared to clamp down on employers who pay non-union rates.
Edit to add: One thing that I do reject, though, is the idea that closed shop is a "bad thing" because it is coercive. This is something in its favour.

Rights are not abstract givens, but rather specific fought for victories. Currently individual rights are in the ascendancy over collective ones; the fact that KJ apparently feels quite comfortable defending his picket line crossing behaviour is evidence of this. Fortunately, people are able to change the times they live in, not simply acquiesce to them saying all the while 'I'm just being a realist'.