Jehovah's Witnesses (others welcome) - A question regarding Matthew 12:36,37...?

Jesus was saying to the Pharisees that they had made the word of God in vain & invalid by making it even more burdensome to men with the unscrupulous teachings & lies that were being spread through them. They were going to be held accountable to the false teachings they were issuing out, thus they will be judged heavily because of claiming to represent the truth of the bible in which they were not & we can see this because they are extinct.