I think he might be referring to the fact that Organic Standards don't allow for transgenic modification of varieties, or what is commonly know as GMOs, due to safety concerns

On the other hand, they allow for varieties made by using radiation induced mutations, which is way less precise and much less tested.

Basically its an ideological position and not based on the scientific consensus.

They also conveniently ignore that pretty much everything is transgenic, the viruses and such that Monsanto uses have existed for a few million (?) years and love to throw DNA around.

The chemical definition of "organic" would include pretty much anything edible except water and salt. The term is commonly used to refer to foods made using more natural-ish processes. Irradiating seeds goes very much against that vibe.

organic rules allow mutation breeding.

The problem is defining a notion of "organic" which is meaningful, consistent and acceptable to / understandable by the public. Many people are shocked by the idea that radiation-induced genetic changes count as both non-GMO and organic. I was, when I learned about it. It seems absurd that food produced this way should fall into a category that gets pushed as "better for you and the planet", when it's a process that's almost as artificial and surely less controllable than GM.

Would you also sell "all natural, carefully enriched uranium based from responsible climate compansating sources" face cream? :)