Who determines who is and isn't a Christian these days?

[nobspeople]

I recently had a "conversation" with a man who attacked me for making a simple, general statement of "I so don't care" on my own personal social media feed. I forget what exactly he said initially, but it was something akin to knowing me personally (I had no idea who this guy was and never spoke with him in my life), then started calling me names like 'jerk', 'pathetic', and 'sad' after pontificating how he's a Christian, how he 'loves the world and all the people in it' and replied to my initial statement 'to make the world a better place'. He then started preaching how we will all have to bow to God at judgement blah blah blah. Later, he even insulted others that took up my position by calling them 'lovers of {me}' and that one woman 'must be attracted to' me (which, of course, they all are but that's another story ), and he ended everything with a 'God bless' statement.

I'm not a Christian by practice, though I was for many, many years. And I'm fine telling someone - especially one that acts like this - that's he's not a Christian as far as I can see. That didn't sit well with him. For days he kept bringing it up and wanting to fight, which I obliged as I had the free time.

When I told Kenny he wasn't acting like a good Christian, he could have said 'Oh well' but he continued - for days - with the insults to not just me but others, almost always ending in a saving face/make it all right attempt of "God bless".
Later, I wondered if anyone has the right to call out someone who is or isn't acting like a Christian.
1) Are Christian to expect to be called out for their foolish behavior (rather or not it is), or should we all just mind our own business?
2) Are Christians (should Christians be) held to a higher standard of demeanor than non-Christians? Surely you shouldn't expect a Christian to defend themselves when personally attacked, but at what point does their defense change from defense to venomous hatred?

[samuelbb7]

Good points.

Judging others thoughts and sins is what GOD does. Paul speaks on obeying the laws of men in the Roman Empire. Judging in a trial is about what they did and their intent. That humans can do. We can say this is wrong or that is wrong.

[nobspeople]

Good points.

Judging others thoughts and sins is what GOD does. Paul speaks on obeying the laws of men in the Roman Empire. Judging in a trial is about what they did and their intent. That humans can do. We can say this is wrong or that is wrong.

Thank you for the response. I think it's good that you point out the difference in judgments so succinctly!