I still think this is generally true and it is a good way to evaluate whether something is true or false (or at least relayed honestly), but in childhood I found at least one exception: the St Nick myth. Here, the lie was told by adults for my benefit (and yes, I see it as such, even today), so it is one of those exceptional cases where almost everyone will lie to you.

I may be the exception to the rule, but my bullshit detector is pretty outstanding compared to the average person. (Or maybe I'm just the eternal skeptic.) I never believed in Santa even from an early age. My mother told me one year when I was extremely young, "you better do (x) or Santa won't get you any presents." I replied, "Mom, Santa isn't real. Even if he was, my mamaw will buy me presents."

But even when I’m been relatively sure on a topic and therefore not likely to change my opinion, I’ve still often found this method useful in another respect: when I debate a topic with someone, it often allows me to refine my own internal ideas and identify weaknesses in the arguments I use to support them.

I'd disagree here. (Of course it's also possible that I could be contributing to your point.) This could also be a methodology of solidifying an uncompromising bias. There are many instances of this on the internet with people that give "debates." (Many of which against people who aren't great advocates for their own beliefs.) They sharpen the argument, but this doesn't necessarily make clear what is objectively unbiased. I've come to terms with the fact that it is impossible in this world to operate without any bias. I have mine, and you have yours.

The objectivity of unbiased reality is always going to be distorted by our empirically driven biases. Unless you've hopped down the rabbit hole of solipsism, this distortion is only tamed slightly when we use intersubjective averaging of a collective perception. But then you have another problem if you believe a majority aren't trustworthy. I personally find that it's useful to iterate through the permutations of possibilities in a very coarse sense and ask first: "does it really matter if my belief is biased? How does it affect the trajectory of my life and the life of others?"

I also like to draw upon the game of poker where my constant mantra is, "does the story make sense?" Mix that with a dash of Occam's razor and two dashes of Hanlon's razor, boom, you have my personal bias cocktail. (Obviously life experience is always important when considering what it is you "believe" in this world.)

Should you ever "go against the tide"?

Emphatically yes, but delivery is important. Hostage negotiators say that the most important thing to do in disagreeing situations is to let the other person know they are being heard. You don't have to agree or lead the person on (it's actually discouraged), only genuinely show that you have given consideration to their perspective without being blatantly disrespectful.

If your goal is truly to limit bias it should be important that we get more people on the same page, as this is what we base what we consider "objective reality" upon. You never can persuade opposition with, "you're wrong, dumb fucker."

That's my two cents at least. I like philosophy. Post some more my friend.