I agree it's a waste of resources but it's been made necessary in order to establish in detail what the law means as the government declined to do this before implementing it.
In a few months time we'll have a list of what isn't a hate crime and possibly some prospective prosecutions to give clarity.
I can't find any examples of what would be a hate crime today that wasn't already a crime last week. If nothing has changed what's the point of a new law?
Edit: Also, you can't really officially say these reports are vexatious when the definition of hate crime depends on the perception of the reporter. And many of them will be anonymous so you can't discern the intent anyway. Personally I'd guess that many are less vexatious, and more taking the p*ss to make a point.