That's true if most mutations produced through and then artificially selected for in modern mutagenesis based techniques, as well as most of the mutations irrelevant to the targeted trait that come along for the ride.

> We know it because hasn't happened often in the last 3000 years

3,000 years isn’t all that long and we don’t know that, what we do know is that no mutation that does that has occurred where it has been in net of cost to the organism useful enough to be selected for an retained, which is a very different thing.

> To blend all those different techniques under the same term would be useless and confusing to both science and consumers

So? The post you respond to acknowledges that they are different but notes “it is insane that mutagenesis (especially in its modern forms) is not treated as even a moderate concern by the same people who hold up transgenics as an existential threat.”

That it is comparatively easy to do a precise, targeted change where you know exactly what new thing will be expressed and change little else through transgenics isn’t in dispute, its the whole reason for that statement.