If you take another look at that report you will see one comment that I thought was especially interesting. One of the people who were proposing that the injection wells were not the cause of the earthquakes stated:

… said, however, that he does not agree with the commission's conclusions and that the earthquakes are a natural occurrence.

"We believe there is a lot of natural seismicity in this area," he said. "This is an area where there's been seismic activity for over 30 years, and we think this is a continuation of that."

So, how much sense does that line of thought make? Look at it this way:

We need to use an injection well to get rid of waste water. So, where should we locate the well?

Hey, hey. There is a lot of natural seismic activity in this particular area. So, that location is ideal. Where could you find a better location than one where there is an earthquake risk?

Is it possible that since there is already a lot of seismic activity in that area the injection well might be expected to actually increase that activity? There is only one way to find out. Start pumping and see if buildings in the area start to collapse during earthquakes.

Someone in that decision making process probably got low marks when he or she took “Logic 101” back in high school.