"Don't bro me if you don't know me."

I've been pondering the phrase, "don't bro me if you don't know me" lately, as a sign of how our ideas about social circles are changing.
Evolutionarily, we're wired to be in continuous units of about 150 people or so throughout our lives (any more and it splits into differing groups, any less and you have to interact with opposing or at least different ones). Changes in that group came from births and deaths (with the occasional disappearance or captive).
Then we get into the industrial era and we find not only larger groups, but layering groups. Family shrinks down to maybe a first-cousin extended unit at best, shrinking down to the single individual in many cases. Then we have an education group and a workplace group. Now each group has differing levels of loyalty and obligation, with conflicts arising between them.
Then more circles crop up. From education we find activities and sports, then universities and from them fraternal organizations. The military changes from every able-bodied man in an area to an individual choice, adding it's own circle. They have different names and natures up and down various socio-cultural-economic scales, but they all operate in similar ways.
But less conflict kicked in (between members of the same circle, anyway) because there were only so many circles anyone was in at any given time. One started with just family, then added education and activities. Then most of those circles went away as you added university or military service or the workplace. Each change in life filtered away members of old circles and introduced new ones.
Now, maintaining connections from former circles was possible, but required effort (letters, reunions, and so forth). Usually, that kind of effort was only viable for those you'd had signifigant experiences with (childhood best friends, war buddies, fraternity/sorority mates who became business contacts, ect.)
But then social media kicked along, specifically facebook. Now, all of these circles coexist not only in space, but in time. Which means the entire spectrum of connection, intimacy, loyalty, and obligation are all lumped under the banner of "friends."
More and more, I'm seeing "friends" being held up as the be-all, end-all of connection and circles, because it's the default setting for many of them ~through time~.
Where that gets wacky is where the ultimatums start.
"If you don't believe in ( X ), then unfriend me now!"
The question being, how strong is your connection to all those in your wide, flat circle?
How many are going to see such an ultimatum in the first place?
How many are going to bother to act, and stay until you kick them out like the last couch potato at the party?
And how long before you find another purity qualification worth a purge?
Are you, in fact, Bro'ing without knowing?
And by how much?
A while back I got one that boiled down to "shun the deplorables!"
And while I didn't voice it, my immediate thought was, "well, I got a handful of deplorables here. Unfollowed onesies and twosies, though that was mostly because they wouldn't shut up, more than anything political. But among them are people who went to war with me.
Your ass, on the other hand, was on set with me for a day. And while you were nice enough and did your job at the time, since friending, you've done little but self-promote and gripe about privledge."
In other words, they bro'd me without knowing me.
Let their bro's write checks their know's couldn't cash.
The waiter ain't quite cutting up their Bro card in front of them, but they are looking at them funny when they swipe it through the Know reader again.
I'll let that metaphor settle back into it's original condition.
But yeah, I think a lot more people would be chill if they stopped and made sure they know before they tried to bro.