Today I learned that TIL Mark David Chapman planned to kill David Bowie and had a front row seat (along with John & Yoko) for Bowie's Broadway show the day after killing John
The irony is that David Bowie’s first #1 hit “Fame”, from the Young Americans album which came out forty-one years ago, was co-written with Lennon who also played guitar on the track. And it was indeed their fame as rock stars which drew Mark David Chapman to stalk them, and subsequently to murder Lennon.
That's not ironic. It's fitting
But it's ironic that something so fitting would happen because you wouldn't expect something so fitting to happen
I understand that irony means an incongruity between what actually happens and what is expected. However, this user (emboldened comment, above) got downvoted for what I believe is an appropriate usage of the word irony.
The original usage of the word as quoted in the post is obviously wrong, it's most certainly a coincidence. However, this user replies saying that it's "an irony that it's fitting because you wouldn't expect it to be fitting". I think it's logical to assume that it wouldn't be fitting for Mark David Chapman to have murdered Lennon and then have plans to murder Bowie just because they co-wrote a song. Am I wrong here? Please explain it simply.