There is more evidence that all Christians should engage in some
foot washing ritual then there is that we shouldn't eat blood.
There is no wiggle room in John 13:14 "Therefore, if I, although
Lord and Teacher washed your feet, you also OUGHT to wash the feet
of one another. 15 For I set the pattern for you, that just as I
did to you, you should do also."
Foot washing is usually explained away with references to the time period. It was really messy walking in dust with sandles.
The Watchtower has made a law out of a similar "OUGHT" at 1 Cor 11:10 "That is why the woman OUGHT to have a sign of authority upon her head." They feel that Paul saying "OUGHT" is a command yet when Jesus says "OUGHT" they ignore
it.
It appears the Watchtower rule makers play fast and loose with what they will accept as a command and what they reject.