This sounds like you are referring to the myth that no heimishe product can be better than the OU since they need to rely on the OU for the basic ingredients.
I never said that, and wouldn't consider that a true statement. What I meant is that in today's world of food production, all Kashrus agencies rely on each other to a certain extent. Especially if you would also want to avoid majors such as OK and Star-K, they definitely rely on the OU for many ingredients.
I don't have time or energy to start becoming a food kashrus expert. Wish there was more of a demand for a chareidy hechsher in the USA..
Just look at DO threads, Pesach program threads, or open up your eyes to what's going on all over, and you'll see that many, if not most, don't care much other than having what is perceived to be (reliable) Hashgocho.
As for the term Chareidy Hechsher, that is such a meaningless term. What defines such. In recent years we've seen new Hechsherim pop up like mushrooms. They slap on the word Badatz or Mehadrin and oilam goilam buys into it. Some might be more competent than others, and some might not have the resources, knowledge, or even skills to operate in today's food production environment (restaurants being a totally different story).
It should be noted, as I pointed out to a friend once, that to be machmir or to say ossur doesn't require any knowledge of halacha. Shulchan Oruch is needed in order to know what is muttar. That being said, you want to know that the authority giving the psak is yerei shomayim merabim, and preferably removed from financial motivation.