It also fails to mention that the organising group is far right. So maybe it evens out?

They mentioned a possible Islamist motive. Which is an important distinction to make because the Westboro Baptist Church doing something is not the same as some random Christian doing something.

Also, you're reading France24. Sticking with state media, but this time German, DW has more:

Investigators earlier said the suspect was an Afghan citizen who had been resident in Germany for around a decade. He had no criminal record and had not come to law enforcement's attention in the past, they said.

The suspect was eventually shot by police. As of Saturday evening, he was alive but in the hospital and in no fit state to be interrogated, according to investigators. As a result, they said, his motives and the reason for his attack required further investigation.

I know he was a Muslim because otherwise he would have been called "mentally ill" rather than a terrorist.

At least they made sure to highlight the rally is anti-muslim. It's just funny following the reporting on the incident so far, as everyone saw the video, how obvious is the bias and tiptoeing around the fact that this was a religiously motivated attack against "anti-islam" activists. But due to the mental gymnastic that does not fit the narrative of doctors and engineers migrants.