What does Matthew 15:2 mean?

To modern ears, it sounds like the Pharisees have come to Galilee from Jerusalem to accuse Jesus' disciples of poor hygiene. It's true that the complaint in question involves them not "washing" prior to eating. Although mothers worldwide likely agree that's a good idea, the Pharisees aren't worried about health. Their intent is to disqualify Jesus as a legitimate rabbi, because His disciples are not following what the Pharisees claim are the "correct" rules of Judaism.

After Moses brought the Law from God, Israel's religious leaders debated how to apply those commands to everyday life. Many of those applications became rules in and of themselves. Each generation committed themselves to following the teachings of the previous generation as a way of honoring the wisdom and experience of the elders. Over time, this meant hundreds of specific rules, with thousands of specific details, had been added alongside the actual Law of Moses. In the worst cases, some of those traditions became convoluted ways to follow the letter of God's law, while avoiding the intent of the commands (Matthew 15:3–9).

Ritual washing before meals, which likely included utensils as well as hands, was a prominent example of these traditions. There was nothing wrong with doing it; however, those details were never part of God's commands to His people. They were man-made traditions about the law, which were treated as if they carried the weight of law.

Jesus and His disciples, however, did not practice this ritualized tradition. God had not commanded His people to do it, and the Son of God did not require His disciples to follow it, either. That's not to say they "never" washed before they ate. But, at the very least, they didn't follow the process according to the standards of the legalistic Pharisees.

The Pharisees and scribes were outraged by this. Highly respected rabbis down through the generations required their disciples to practice this form of handwashing. How could Jesus or His disciples be considered respectable followers of God if they did not practice it?

Jesus' response shows He does not even respect the accusation, since it's coming from a place of deep hypocrisy (Matthew 15:3).