That statement is entirely correct; the US is the only country ever to use nuclear weapons in combat. Everyone else has only ever tested them, or used them as threats/deterrence.

Assuming you didn't miss the "in combat" part, this may be an English issue: To be a "user" of nukes here means "has used nukes in combat", not "has nukes for use in combat".

What other countries have used nuclear weapons in combat?

Did a whole nuclear war go by without my noticing?

Not an entire nuclear war, but you may remember the end of the second world war.

you all are being disingenuous by the mere highlighting of “who used nuclear weapon”, as opposed to “who is now able to use”.

But, please do soldier on.

The post read "... only user of nuclear weapons in combat", and you replied, "… only user …?" You chose to leave it at that, and in English, this implies that you disagree with the fact of the two quoted words, "only user", not that you disagree with the point the parent was making via that fact. If it is actually the latter, you should clarify. It's very reasonable for everybody to take your post the way they did, and has nothing to do with politics or dishonesty.

Also, the sarcasm is unnecessary.