My point exactly. LOL!!!
Indeed, you have a point. However, it lacks merit. The real answer in using radiocarbon dating for any features older than 50ky is "more than 50ky"; which of course, includes 4.6 Ga.
Think of it this way: you have one meter stick and try to measure the width of the Atlantic Ocean. Well, the answer is, of course, NOT 1 meter, but
more than one meter.
Consequently when we see an age of something like 40ky, or 50ky, or 60ky; we are really seeing something that is OLDER than that. You will notice, for instance, that all of the objects dated by RATE that tend to cluster at 40-60ky. This is very suspicious to me, suggesting that they have attempted to date diamonds (for instance) that are beyond the 'meter stick' of radiocarbon dating.
Now, the question is 'why is there any 14C at all in these objects?' The most simple answer is that it is generated by low level, natural radiation acting on nitrogen, one of the more common elements in the earth's crust, atmosphere and biosphere. It is interesting that some materials do, for all practical purposes, contain NO 14C. What is the difference? My bet is on the possibility that they had no N and no uranium to begin with and, hence, generated no 14C.
My whole point is that we are looking for a DATE. Not for an amount of 14C in a material. Always look at the generated date and you will get a clue as to what is going on.