You an see his reply here. Bird does a much better job than I did picking out the most important mistake. Reading Bird, I think it might be enough to say that Carson sees confusions that make a task difficult as reasons to believe the position is not valid.
Liberals mess up the definitions of many things that Christians hold dear. We can’t drop terms and concepts and imperatives just because liberals pervert them or others are mistaken about them.. So just because someone turns “The Kingdom” into a wrong agenda, doesn’t excuse us from pursuing the right agenda.<>