Oh, an agnostic.
There is something to be said about groups of people that hold similar ideas because their similar way of thinking lead them to similar conclusions. It's a very important exception to the OP's description, where the group came first, and may even be the most common kind.
(Of course, the question to answer is why do those people think in similar ways.)
> part of the group of software engineers by trade
I'd bet that one lead you into adopting some values.
You probably also have some abhorrence towards formal chaos (the ones that causes unpredictability; many are not even able to accept it exists) and want to improve every system (simple or not) you see.
On the more traditionally politics kinds of thing, you probably value freedom of expression to a very high amount, like other highly educated groups, but also probably value personal freedom and personal initiative. Those often come in an intensity that leads to some bullshit levels of belief in self-determination (like in not believing you share group values) and personal responsibility; but beliefs change faster than values, and many people tame those down with time.
Invariably, in every discussion, they'll trot out this sentence: "You <opponent group name> people always think <notion>".
For example: "You Liberal party voters always support lowering taxes" or somesuch sentence.
I point out that I didn't vote for the Liberal party.
"The Labour party voters are the same!"
I point out I didn't vote for Labour either in the most recent election either.
"Err..."
-- at this point their brain locks up, because they're expecting a tribe-vs-tribe fight and they have no idea what to do when they discover I don't actually belong to their "enemy tribe".
Even saying you’re !group makes you explicitly a member of the !group group!
I've come to realize that "white male software engineer" is one of the groups with the highest ratio of priviledge versus priviledge awareness.
(Disclosure: I belong to that group as well.)
> I don't feel like I'm a member of many groups.
And this part:
> I suppose you could say I'm part of the group of Caucasian males by birth or part of the group of software engineers by trade,
So, you are belonging to three priviledged groups. Male, Caucasian, software engineer. It's easy to overlook this group membership, since it silently represents priviledge. Those outside these groups definitely notice that they are not in them. Ask a discriminated woman, a discriminated non-white, or an amazon warehouse worker.
That's why I pointed out that it's easy to forget group membership that confers priviledge.
> Also you're assuming a lot about my background
No, I went by exactly the information you conveyed yourself. See above.
> The power of reasons is an illusion. The belief will not change when the reasons are defeated.
So privilege plays an interesting role. Unaware privilege - failing to see ones own circumstances, failing to assess how we fit in the world - is almost the same thing as non-reason. I suppose there could be a class of people who are like, "I am totally privileged, and somehow I delude myself and don't notice, but in every OTHER way I am totally reasonable." That could be a subgroup. But probably not a big one?