[avar]

What you're saying here isn't relevant.

The 1929 Geneva convention is talking about the segregation of POW's who before capture would have been part of the same organized armed forces.

The only reason to specify that POW camps should be divided by nationality and race is to e.g. ensure that black French colonial troops aren't going to be using the same proverbial bathrooms as white continental French troops.

In the 1949 version of the Geneva convention this clause was eliminated, and replaced by wording which presupposes racially integrated armed forces, or alternatively makes it deliberately ambiguous as part of "customs". From Article 22[1].

    The Detaining Power shall assemble
    prisoners of war in camps or camp
    compounds according to their
    nationality, language and customs. 
    [...], except with their consent.

1. https://www.ohchr.org/en/instruments-mechanisms/instruments/...