Catholic/Christianity question

I think what blurs the distinction most are those people who refuse to be identified by any other term but "Christian." I've run into them and when asked, they refuse to get specific, they eschew any subclasses in what seems to be an effort to be everything to everyone.

"I am a Christian."
"Catholic? Protestant?"
"No. Just Christian."
"But there are numerous branches. Methodists, Lutherans, Episcopalians, Seventh Day Adventists..."
"Nope, Just Christian. That's all."
"Are you Born-Again?"
"No. We've always been just plain Christian."
"I don't get it."
"Heathen."

So they clearly hold themselves apart from the other sects. Even Born-Agains, who have a peculiar distrust of the traditional sects, will accept being a sect unto themselves.

It's a "squares are rectangles but rectangles aren't squares" kind of existence for them.

Jam it back in, in the dark.