They have a point. It's not a violent crime. Unless, of course, said flasher beats the victim with his penis. Then, I think that's sexual assault, which is a totally different animal. Also, let's not confuse flashing with streaking, that wacky '70s fad.
Flashing is closer to molestation in mindset, whereas streaking is fun-loving exhibitionism.
First, you have to determine if a flasher is worth aggressively pursuing. I say no. Hell, we barely even kill our killers in this society, much less the pervs. According to the paper, the officers let him walk out of the store and get into his car. The officer was dragged along by the suspected flasher's truck for about 50 feet.