Well, the word baptism means to dip under water, so baptism for the purpose of cleansing only applied to cups and dishes etc. being washed by being fully immersed in water, this did not apply to humans in that sense. The hand washing was done up to the elbow, not fully immersing the body.
According to Mark 7:3-4....
For the Pharisees and all the Jews do not eat unless they wash their hands up to the elbow, clinging to the tradition of the men of former times, 4 and when they come from the market, they do not eat unless they wash themselves. There are many other traditions that they have received and cling to, such as baptisms of cups, pitchers, and copper vessels.
When the Pharisees complained to Jesus that his disciples did
“not wash their hands when about to eat a meal,” Jesus rebuked the Pharisees. Not because he favored eating with dirty hands, but because the washing was part of their oral tradition. It was a religious ritual. Hands had to be washed before and after the meal and sometimes during the meal, with special water, and in different ways with different foods. Knowing all the intricate nonsense the Pharisees in those days commanded concerning the washing of hands immediately gives understanding of why Jesus rebuked them. It shows a religious ritual was involved, that it was a part of the oral tradition of the Jews that Jesus said made void the Word of God, and it eliminates any erroneous thought that Jesus favored eating food with dirty hands. (Matthew 15:1-6)