No, the main case has never been that they are not approved or experimental.
That is just the non-technical summation.
The actual argument against these mRNA injections is that their description of how they work is bizarre.
The CDC site claims that even though they are intramuscular injections, they somehow get into our cells, and there are translated by our own ribosomes, in order to get our own cells to grow spike proteins.
Not only does that sound wrong since cells deliberately keep things out, but it would seem ridiculously dangerous to reprogram out cells to make spike proteins and even worse to make our immune system target spike proteins our own exosomes routinely use.