Let's assume I didn't know about vaccines and I went to ask for advice to someone. How would I know if what they told me was good advice?
I would ask myself, are they an authority on the subject? Where do they draw the advice from? Who says they are an authority? What did they have to do to earn that authority? Do other authorities say the same?
Are mormons authorities on logic? Why trust advice about logic from someone that doesn't follow logic?
A liar can say that lying is bad. A killer can say that killing is bad. It just so happens that the advice is good, in spite of who said it.
Yes, it's emotional to disregard advice you know is good. However it is a logical reaction to have.
It is logical for humans not to trust or accept advice from a hypocrite, even if that advice may be good. It's not about the advice itself, but about who gives it. That was my point.
Unfortunately humans have emotions, and those emotions factor into our so called "logical decisions". To ignore our emotions is to pretend we are machines, and machines wouldn't be in these situations, as a machine wouldn't give advice it doesn't follow itself.
Now, if we were machines, sure, if the advice is good, it's good, doesn't matter who gives it.
Furthermore, if I already know the advice is good, did I receive advice?