He’s not so hot on standing up for the ‘biblical truths’ that say you should turn the other cheek. Or go the extra mile. Or that you should sell all you have and give the proceeds to the poor. No sir. Those are biblical truths that demand something of Christians themselves so of course they feel perfectly at liberty to disregard them.
This is not what Jesus is saying here though. He clearly means ‘do not judge others unless you’re prepared to be judged yourself’, which, we can only conclude, Christians are happy to have happen to them. They judge others and in so doing open themselves up to judgement; Jesus is very fond of this kind of yin and yang, measure-for-measure arrangement:
Judge not that you be not judged. For with the judgement you pronounce you will be judged, and the measure you give will be the measure you will get (Matthew 7.1-2).
It could also be the case that Jesus is referring here to God’s ultimate judgement as well, in which case those condemnatory Christians who believe that being ‘saved’ allows them to escape the final judgement are in for quite a shock. Still, they can always use the ‘I was only defending biblical truths’ excuse.