Establishing genetic descent is, by definition, a "legitimate" way of figuring out descent.
You are not addressing the point you claim to be addressing. The point is that homology is not a legitimate way of figuring out descent. Due to the many examples of apparently homologous features, functions, and even genetics in completely unrelated species homology cannot be used as evidence for descent. Indeed, the fact that homologues are to be found in widely divergent species is proof of intelligent design and a disproof of evolution.
I am perfectly within my rights to address straightening out your nomenclature, as well as your claims, in any order I care to.