Not sure what media culture world you are living in but the short answer is it matters HUGE
I don’t live in any media culture world. I sincerely don’t know what you are talking about.
Most of the mass attacks in this white-majority country are carried out by white people. Which means the odds are that THIS attack was done by a white person or persons.
So what?
Just to be clear I think it’s quite important whether or not this attack was carried out by jihadis or not, and whether it was carried out by an organization or not.