Even if this incident doesn't fall under the definition of terrorism (and I don't think it does based on current evidence), there's been a clear trend historically of double standards. They never classified the Charleston shooting as terrorism either and that had clear political/ideological motivations.
Did the Nazi protester who ran over the girl a month or two back get classified as a terrorist?
I'd also wager that if this guy happened to have been a Muslim we wouldn't see such caution in labeling it a terrorist attack. It would have happened after 5 mins.