The headline says Ars fired the reporter, but AFAICT the article doesn't include any facts that indicate this. All we know is that he no longer works there, and that Ars refused to provide any additional information.
It does include two facts:
1. That the reporter's bio on the webpage changed "...is a reporter at Ars" to "...was a reporter at Ars". On the one hand, that's pretty thin sauce. On the other hand, that's not exactly the sort of change that gets made randomly.
2. They reached out to the various people involved, and although nobody has confirmed it, it's also the case that nobody has denied it.
We're not actually entitled to know the exact details of someone's job ending. They worked there. Now they don't. That much is the bit we're entitled to.