My guess: because none of their other apps are in the store (they ship via developer id signed apps outside of the store), the reviewer didn’t find any other ap

My guess: because none of their other apps are in the store (they ship via developer id signed apps outside of the store), the reviewer didn’t find any other app they made and decided that an extension like the one they were making needs to be from a company with a more reputable AppStore account. They should of course also have checked what Malwarebytes does outside of the store, but they didn’t which might or might not have been actual internal review policy