The word I think of is "skeumorphic", though that's not 100% the same thing here.

I believe this is the word that best fits.

skeuomorphic - Pertaining to skeuomorphs, obsolete design elements which are retained for familiarity or out of tradition, even though they no longer serve any functional purpose.

Ritual.

Is it any more fake than the tradition?

Hah I wonder how much of this we do presently without realizing. Shaking hands maybe

What do you think the original function of shaking hands was as compared to what it is today?

There was this funny study that found that people were more likely to hold their hand next to their nose right after shaking hands. From this they concluded that hand-shaking is a non-intrusive way of smelling a person you just met.

showing that you're not holding a weapon.

...in one hand.

It also shows that you trust the person not to use a weapon. One hand may be clear but you trust that the person doesn't have one in the other.

Symbolic?

Vestigial?

Cargo cult!