@reasoning logic,
My answer for the forum question, "How can we be sure all religions are wrong", is just as simple as looking at the people who come up with the religions and follow them. Human error alone is evidence to verify there is surely something wrong with all manmade religions. At that level, all religion is philosophy. Small "p". Philosophy, big "P", affects things, situations, people, indeed, but is not necessarily True. Then again, I'm sure this would be chalked up as a "philosophy", by most of the so-called religions. Even the lack of a spiritual belief is still a religion. So yes, atheism is a religion as well. Buddhists are divided as much as scientists are. The list goes on and on.
But I will say, for the Experience of anything "firm", there must be Truth. It is safe to say that all religions have a piece, some more than others, of that Truth, and so, yes, all are "wholly" wrong.
But the existence of the Experience of Firm is not able to be questioned.
When coming from this POV, all that is not 100% Firm, is a "Water".
Though some things may appear Firm, for a time, whether or not we have knowledge of the crumbling makes no difference in the end, as it is still a Water, just without Experience. I apologize if that sentence seems a bit hard to understand, or is grammatically exaggerated.