The Watchtower is always concerned about things being done "JUST SO" when it comes to divine commands.
A command is usually set forth with words such as shall, should, ought.
When Jesus washed the feet of his disciples he said:
"Therefore, if I, although Lord and Teacher, washed your feet, you also OUGHT to wash the feet of one another"
The pope obeys Christ's foot washing command but JW's don't.
What's the JW's excuse? They say that was just a "one-off" example and not an empty ritual to be repeated. They finish by saying feet washing was a traditional courtesy because people wore sandals and their feet got dry and dirty.
They apparently didn't read the rest of that account.
Jesus says in John 13:15 "For I set the PATTERN for you, that just as I did to you, you SHOULD do also"
Siince JW's weren't there, the default understanding of what Jesus did has to be his own statment.
Isn't a pattern something that is repeated. Those who have actually engaged in the Maundy Thursday practice, talk about the humbling effect it has on one's ego.
The reasoning behind ignoring the ordinance of foot washing could be applied equally to baptism by immersion in water.
And to say that it was a cultural courtesy could be applied more appropriately to something like women wearing head coverings.
Just a little something to bring into the conversation as you get together with your witness relatives after the memorial.