[rincebrain]

I don't think I said I agreed with them, or that the position had no flaws, I just said I thought their stance was sincerely held.

People can earnestly believe illogical or inconsistent things. Arguably those are even easier to get stuck believing, as you already had to accept some friction in the inconsistencies earlier in your internalizing them, so now you're even further into sunk costs around it.