There's just no pleasing some people! Jesus is talking about the leaders' reaction to both John the Baptist and himself.
When John came preaching a message of repentance so as to prepare for the coming Messiah, people began to come to him to be baptized. This didn't make the Jewish leaders happy and so they complained.
Jesus came along, preaching the Good News of salvation and they were even more upset. They compared his behavior to John's and complained again, even stating that John's disciples obeyed the law more than the disciples of Jesus. I guess they forgot that they shouldn't judge.
We often do the same thing. Sometimes we even pass judgment on the same person – twice!
We might have a friend or relative who has gotten into trouble. It could be something illegal or it could be an addiction that is out of control. We judge them, not their behavior, and decide to turn our backs on them.
Then, they clean up their act, pay for their past behavior, stop using whatever they have become addicted to. Do we welcome them back into our lives? Some might, but others will say that it's all an act and they are still not worthy of our love.
This has happened to well-known figures in the media or sports as well. One mistake and that's it! Judge not lest you be judged is not part of the make-up of some people.
Again, I'm not saying that we should leave money hanging around if someone has had a problem with theft or gambling, or that we should offer an alcoholic a drink once they have achieved sobriety, but we should look at the person and give them a chance.
Both John the Baptist and Jesus were judged unfairly, we need to be careful not to fall into the same trap.

