I'd like to offer some advice to make things go a bit more smoothly. There's a widespread view that all beliefs are political, you can't be apolitical, and anyone arguing for a belief opposing yours must be an enemy. To me, that view is pretty much a type error. Beliefs are value-neutral. Only arguments for or against beliefs can be political or not.
More specifically, some arguments are rational (based on evidence) while other arguments are political (based on who benefits and who loses). You can be a very civil person, but still reach for political arguments when defending your beliefs, and thus cause net harm. Or you can be a rude person, but drawn to arguing based on evidence, and thus cause net benefit. It's up to you.
Now go forth and make a flamewar :-)
So if people choose to believe in something because that has certain consequences - then a belief can be political.
EDIT: To expand on this a little... It seems to me that you divorce a belief itself from its consequences. As there are a lot of beliefs that have immediate and direct political and social consequences, i think that this separation is questionable.
If you have a belief, you probably will act on that belief. Having a belief and _not_ acting on it _at all_ seems rather useless and abstract to me. I'm not saying that this doesn't happen, but in general, if some person has a belief, he (or she) will act on that belief.
So, to be blunt: for some beliefs, having them is a political act.
Formally:
1) A => B
2) I would really like B to be true, because it has some benefits.
3) Therefore A must be true.
If we are in search of truth and want to build a consistent model of the world then we just can't accept this kind of reasoning.
Also, even if A really turns out to be false, it doesn't mean that B can't be true and our world will forever be sad i.e. Even if it turns out that all people are not created equal, we can still live in just and enlightened society which treats everyone fairly.
And of course the implication between A => B may not even exist. Is it really true that if all people were created equal the society would benefit?
> If we are in search of truth and want to build a consistent model of the world then we just can't accept this kind of reasoning.
Yes, you can. It's called generalizing. Remember, we're not doing math here, this is ethics.
Think about all the different situations where being treated equally to someone else is a good thing. Now you generalize that into "everyone is created equal", and that turns into a justification for all these situations.
If you want to criticise the generalization into A, there is a way:
Construct some C so that
1) A => C
2) C is not beneficial
Alternatively, you can attack the implication "A => B" or you can question whether or not B is beneficial.
The valid generalization would be "everyone should be treated equally" not "everyone is created equal" which is a totally different thing.
EDIT: I think what you're doing here is criticising A by constructing A' and arguing that it is better (by having the same consequences while being less general). That is a good way of criticising the generalization as well.