It wouldn't have been true to say it's genetic modification. Many viruses do perform genetic modification, and it's theoretically possible to develop mRNA thera

It wouldn't have been true to say it's genetic modification. Many viruses do perform genetic modification, and it's theoretically possible to develop mRNA therapeutics that perform genetic modification (by having the cell construct the protein machinery required to do so) but mRNA vaccines don't do that. Doing that is hard, and unnecessary. It's like the difference between an image and a computer program. Sure, you can sometimes construct a WebP image that executes arbitrary code, if you have enough information about the execution environment, but that doesn't make all (or even most) images programs, and it doesn't mean we should delete all the diagrams from our textbooks. Or the difference between a spoon and a razor blade. Metal can be shaped into sharp blades, but that doesn't mean we should swear off putting cutlery in our mouths. More to the point, I don't see the argument for not calling mRNA vaccines vaccines. Did you think that live attenuated viruses don't have RNA in them?