It's minus 28 outside, I am drinking sparkling wine, and Glasgow Warriors Vs Edinburgh today, Scotish rugby derby

But, motivation is not important. What is important is that all these people are dead or injured.

I have a suspicion that the perpetrator might be psychotic, which, if true, raises questions on how he was working as a psychiatrist. In any case, we'll find out at some point, because he will surely be assessed.

The next thing would be for someone to drive through a women's march due to fear of patriarchy. Or mass-shoot people praying in a mosque because of fear of over-christianization.

It would be wise to wait about the motivation. Because driving through christians because of fear of over-islamization sounds rather absurd.

Which, just to put it out there, is one of many alt-right conspiracy fairy tales made to scare people. Apparently they work.

I can't find any source saying he hated Christianity. You seem to, again, be making up facts so they fit your interpretation of things. All sources I have say his most likely motive was fear of "over-islamization".