Why are so many people calling the Rick Chow verdict controversial if the jury believed he was protecting his son?

Genuine question because I'm trying to understand the opposing viewpoint.

From what I've read, the jury heard evidence that the teenager was armed and that Rick Chow believed his son was in danger. After hearing all the testimony and evidence, the jury found him not guilty of murder.

If the jury concluded that Chow reasonably feared for his son's safety, wouldn't that make this a straightforward case of self-defense or defense of another person?

I'm trying to understand why so many people seem to view the verdict as controversial. Is it because people disagree with the facts the jury accepted, or because they believe someone who pursues a suspect should lose the ability to claim self-defense later on?

What am I missing?