You seem to be missing the point. An individual can believe whatever they want, but the assertion that they aren’t worshipping the same god as someone else falls apart because it makes assumptions about someone else’s beliefs. Asserting such as a third party is even more ridiculous, and the idea that someone who shares faith with neither of the principals can make that call is yet more ludicrous and arrogant. As a direct logical result of no one knowing anyone else’s beliefs, we have to fall back on the historical facts at hand, which @anon61221983 has detailed above.
