Why? What goes into the mouth is not what makes people unclean, it is what goes out of the mouth. Jews consider their Kosher diet as an act of obedience to God.
You simply don't know what you're attempting to talk about. Context is everything...
1] Then came to Jesus scribes and Pharisees, which were of Jerusalem, saying,
[2] Why do thy disciples transgress the tradition of the elders? for they wash not their hands when they eat bread.
[3] But he answered and said unto them, Why do ye also transgress the commandment of God by your tradition?
This story is yet another account of Jesus confronting the Dogma of the Pharisees. Not a green light to eat that which God has commanded otherwise. The Phariseeical handwashing was a man made tradition, observed, and practiced by the Pharisees. Further it is applies specifically to the eating of bread, or matzah. Which is specifically what was being eaten. Context is everything.
Additionally to complete the ritual a recitation is made.
Full Text of Netilat Yadayim
בָּרוּךְ אַתָּה ה׳ אֱלֹהֵינוּ מֶלֶךְ הָעוֹלָם אֲשֶׁר קִדְּשָׁנוּ בְּמִצְוֹתָיו וְצִוָּנוּ עַל נְטִילַת יָדַיִם
Baruch ata Adonai, Eloheinu Melech ha-olam, asher kidshanu b’mitzvotav vitzivanu al n’tilat yadayim.
Blessed are You, Lord our God, King of the universe, who has sanctified us with Your commandments, and commanded us concerning the washing of the hands.
What is interesting here is that there is no such command in the Torah that requires this. This is tradition. Origin of this tradition..?
Origins of Netilat Yadayim
The tradition of netilat yadayim prior to eating bread originated with the rabbis of the Talmud. It derives from various practices concerning ritual impurity from when the ancient Temple stood in Jerusalem. The priests who performed the temple rituals were given gifts of oil, wine and wheat that could be eaten only after ritual washing. For various reasons, the ancient rabbis extended this practice to all Jews before eating meals. Some sources suggest that the practice was instituted so the Temple’s washing ritual would not be forgotten.
But in the end; this passage is about Jesus confronting the Pharisees for placing their Dogma, on par with the Law, and to basically let it be known that God never said eating with soiled hands would make one impure. It is not however a countermand to any command God has previously laid out.