Convinced atheists can be just as exclusive and rude as
anyone else.

I don't dispute that some atheists act with something very similar to religious conviction. What I dispute is that atheism is inherently a religion, or inherently involves faith (for the relevant senses of 'religion' and 'faith').

It is uncommon, in fact, for an atheist to be tolerant, to
refrain from "of-course" tone of voice when expressing such beliefs as

It's not intolerant to be confident in one's beliefs. It's not even intolerant to let other people know you think they're wrong.

evolution and cosmic age, both of which are founded upon inference and each
of which can be shown to be flawed.  Even if they are not fatally and only
slightly flawed,

To me, a belief is "flawed" if and only if can be shown to be either unjustified or false, which is not the case for either evolution or cosmic age.

 they are still put forth as absolutes

That's a problem of particular atheists, not of atheism.

and anyone who
questions them is put onto the defensive.

If I were a theist told by Paul Ireland that "there is NOT ONE BIT OF EVIDENCE THAT GOD EXISTS", his obvious mistake would put me on the offensive, not the defensive. I suspect that some of the defensiveness that theists feel has more to do with the defensibility of their worldview than with the rudeness of atheists.

I could dispute almost all of it, but I'd have to first
sell everyone my re-translation of the gospels (the metaphysical one that
directly contradicts the very things you cite).

I know of no wiggle room in the translations for the verses I cited. A better tactic for a liberal Christian might be to claim that the gospels contain misquotes, and then come up with some excuse for why a benevolent deity would leave such an imperfectly-recorded revelation.

the conversation wasn't intended to be a
disprove-prove Christianity thing, it devolved toward that by you and
others

Edward reported that Epstein debunks Christianity, without any details. You were the first in this thread to start introducing evidence (about Jesus' positions) on the debunkedness of Christianity, and so I cited some contrary evidence.

taking issue with points made in support of the real topic, which
was that most atheists conduct themselves very religiously

If you had said it that way, I wouldn't have chimed in. :-)  But you wrote "Atheism and Objectivism are religions too, you know".  (That "you know" comes across with something of the "of-course tone of voice" you mentioned above, by the way.)

I agree with your central point that those of us advocating increased liberty should seek common ground rather than differences.  The more carefully we choose our words, the less likely we are to create the appearance of differences that aren't really there.