But Jesus/God is shy, lazy or apathetic. He could easily say who are Christians and who aren't but does not .
These are viewpoints that neither JWs nor Christians would accept of course. So if it's only that basis that both are Christians then there's a problem.
It's as if atheists perceive the situation like two children arguing with one another:
First child: I'm the king of the castle!
Second child: no I'm the king of the castle!
Adult: you are both king of the castle, now be quiet!
That's the sort of level at which atheists seem to think they have "settled" this issue of who is Christian. The problem of course is that religious believers don't perceive themselves as squabbling infants and they believe the issue under dispute actually matters.