As late as the early 20th century, soldiers fighting on foreign soil, even though identified, tended to have been buried in long trench graves as they could not be taken home.
Burial customs differ widely from society to society.
We do not know what the customs were for the burial of a group of claimed bodies at the time. None of the skeletons published so far shows any traces of wounds typical for ancient warfare. This is a good point, as the mass graves are not.