A lot of scholars are hard on Jesus' criticism of the Pharisees. He is too hard on them they say. They cannot be that bad.
You see the biggest issue is that the law is spiritual and can only be fulfilled by the heart. The law is summed in:
"Love the Lord your God with all you heart mind soul and strength and love your neighbor as yourself."
You see the many apparently external requirements of the law are in reality internal.
We find it often in questions of if we are are required to do this or that by God. Often we find ethical discussions have reluctance built into the discussion. Can we not act and be law following?
The whole issue is that we often ask the wrong question. We ask "what is permissible" and not "what is the will of God." We ask "is this forbidden" and not "is God glorified."
Jesus tries to make this explicit when he says the inside of the bowl needs to be cleaned not simply the outside.
You see a commandments of God always have an internal aspect in nature. There is often an external or action aspect but they law always goes to a heart issue.
You see this is why there are is so much dead faith in the world which Jesus warns of. We can do all the right things and say all the right things but true faith comes down to an internal heart state of where our love for God begins to overflow into the rest of live.