Indeed, neither "Richard" or that clown, Chapman, for that matter are able to have a normal discussion about the evidence. All they do is repeat the same old weak and implausible narrative and ignore and dismiss anything that does not fit in that narrative. It reminds me of Albert Einstein's famous line: "Insanity is doing the same thing over and over again and expecting different results."
Oswald is linked to the rifle by the evidence (i.e. documents, prints, photos, witness testimony, serial number, PO box, use of an alias associated with him). The rifle is linked to the assassination by overwhelming evidence (i.e. found at the crime scene, fired bullet casings, bullets and bullet fragments from that rifle). Your rebuttal is simply that all this evidence could be faked or planted. That is not a basis to raise any doubt. It is an exercise in applying an impossible standard of proof to the facts and evidence to raise fake doubt.