AGPL and Commercial Add-On can they do that?

I am confused. How does SuiteCRM have a store that seems to promote the commercial license of Add-Ons. Don’t those Add-Ons fall within the AGPL derivative works because they have to hook into the system?

I am not a lawyer, but I guess an add-on is not a derivative work, it’s a separate piece of software. SuiteCRM still works the same as I always did, if you don’t use any add-ons.