Wouldn't try to. We will each of us have our own private opinions about the spiritual state of others on the thread. My only request is that Calvinists will only publicly identify those holding to Fatal Heresy as definitely being Non-Believers. In this way we may easily distinguish between those who we preach Warning, and those to whom we preach Correction.
As to the private doubt of his regeneration to which his bad-spirited language might provoke you, I know where you are coming from. It's just a matter of choosing which battles we want to fight, and/or how we are going to fight them, that's all.
best,
OP
I didn't see the post that you're referring to, but here is a little of the type of shorthand I use for evaluating spiritual maturity/immaturity:
Show me a Christian who can't say "damn", and I'll show you a neurotic legalist.