It is hygienic to wash hands before eating. That practice became a traditional way for religious people in Israel to express their piety. Successive generations had created a web of religious rules covering exactly how the people should live their daily lives. Although many of these were based on the Law of Moses, the details were added over the 500 years before Christ, so that the traditions were very different in concept to the Law of God.
 
Even Jesus' accusers did not dare say that ceremonial hand washing before every meal was an instruction from God. They were content that as long as the tradition was maintained, there would be stability in Israel. Jesus did not command His disciples to become clones of the religious establishment, because the matter had not been commanded by God.
 
When questioned, Jesus challenged their integrity. They had developed a clever religious way of avoiding financial and care help for elderly relatives - by publically declaring their wealth as 'set apart for God' they escaped any family financial liability. In practice, they simply spent their money on themselves and the poor parents had little support.
 
Jesus exposed their duplicity. There is no point in keeping a set of humanly devised religious rules if their effect is to undermine what God has actually said. We can do the same thing. It is easier to make up little rules which we think we might be able to keep, rather than to struggle to obey what God has clearly commanded. Take stock of your own religious practices, and see if you are genuinely obeying the Lord, or simply keeping in with other members of your religious club.