What I mean when I say "Christianity" is a "Red Flag" (for me personally).

 "Red flag" doesn't mean someone's guilty of something.

It just just means they've given cause to worry.

In some cases, a person's faith works out GREAT for everyone whom their theism impacts.
But usually (really, in most cases) it does not.

I understand that (libertarian) Free Will is an illusion.
And I realize most "personal (Abrahamic) God" theists lack the awareness it takes to really track their true impact on other lives.

So then all we can really do is make as broad spectrum of real education available, help build healthy societies, and hope whoever has a harmful religious narrative matures into a healthier form of spirituality.

Typically, an "atheist" will denounce the entire concept of "spirituality" as childish and toxic nonsense.
But that's not where I'm currently 'at' about it.

I think spirituality can be
a legitimate domain of exploration, discovery, and growth.

It's just usually not.
And whenever it's not, the person won't be able to realize it's not.

Personally,

I'm a big fan of certain Native American spiritual and cultural narratives.

There are also some things about Buddhism that seem very right to me. 

As for Christianity, it's just a religious category or theme.
As such, it doesn't really tell me anything specific about a person. 

For me, it's just a "red flag" because:
 it usually means a person's view of me, and of other people, ... is going to be very socially problematic.

I think most people in general are permanently disabled when it comes to their ability to be

their half of a healthy and durable marriage.

Even the rare good people (of our world) only make a good partner for someone they are really compatible with.

Good people will usually marry the wrong person.

But the reason that 'category' of religious faith
is a "red flag" for me is:

Everyone (yes; everyone) who is in a (literal) "close personal relationship with the God of Abraham",
IS in an abusive relationship;

with: * that conceptualized super-parent,
and with/under * the people who help make it "real",
and with * their own self.

They're mistaking that abuse for benevolence; as explained in this video: 



It tells me: they very probably don't know what a fully healthy/ mutually-respectful relationship looks like.
They CAN (in some cases) still HAVE a healthy-enough relationship with another human being.

Well, some few can.

But if they stumble into one,

it's a happy accident.

They'll have 'beaten the odds';
which their religious-culture will have spent years stacking against them.