How is Slifkin unreliable? He brings sources for all his statements.
All his statements are quoting rishonim, geonim, acharonim, etc.
He often misrepresents or misunderstands their words. I’m not an expert on his writings, and the little I’ve seen I don’t remember, but I do remember looking up one or two of his sources and finding that they didn’t say or mean what Slifkin claimed.
Even if all his sources were accurate, you can’t pick and choose based on what you think fits better with science. We have a mesorah.