Look at the last eight words of this statement:
we wouldn't want to be held responsible for.
McCain is admitting right there that he could have been held accountable for what he said. Thus, he is admitting that it was inappropriate.
Now let's not head back to the point of "Well McCain said things..." anymore. We all agree, him included, that it was inappropriate.
Now as far as McChrystal, it is clear from the tone of the article that a lot of this kind of talk (trashing the chain of command) was going on in his office. We don't have specific quotes, but you would have to be willfully blind not to see it in context of the article.
So either McChrystal said it himself, tolerated it from his staff, or allowed a reporter to make it up whole cloth.
In any of the above scenarios, it was irresponsible action from the General that allowed this to happen.
I have not heard from anyone who has served in a Senior military position that has not shrugged and said "Yep, he had to go." after reading the article.
Nor have I...to include an 06 who recently left McChrystal's staff. He said he had great admiration for the general, but knew he had to go.