Because the general consensus appeared that he did nothing wrong and that everything he did was justified.
Because I think the officer at issue didn't do anything worth getting fired over does not mean I think he (and others) can't improve, and that's where I think emphasis should be. This incident is a learning moment.
But I'm still waiting for more investigatory information before I form a comprehensive conclusion about the matter. For instance, it would be helpful to know what other officers on the scene were running after, and why. Knowing the number of officers on the scene and their order of arrival should prove enlightening too. And that radio transmission made just prior to the bikini gal episode could be very helpful in understanding what was on the mind of the officer and why.
There could easily have been concealed firearms in that crowd, and probably there was given we're talking about an incident in Texas. Officers realized this. There was report of violence. The crowd was anxious and mouthy. Several individuals were failing to remove themselves from the chaos, which caused needless distraction. I'd have been as loud and as obnoxious as necessary to restore order so I could better focus on whatever presented the greatest danger, if any danger remained. I'm mostly glad that we're not talking about grieving parents.