You're not reaching the people who are doing this, though. And you're really playing up an us vs. them mentality that helps nobody. Reports like yours are coming in around the world, but especially in the US. Look at all of the people who went to Florida for spring break. I have friends in Arkansas, Oklahoma, California and Illinois who are all saying there's a sizeable chunk of idiots going out without a care. This is a worldwide issue spread out among a group of stubborn assholes. Telling people in the valley its their fault helps nobody. One of the other posts, similar to yours, is from someone who checks IDs in a coastal community and their claiming it's Washington and California residents they're seeing.

But, ultimately, you're preaching to the choir here. The subreddit is pretty pro-self-isolation and pro-social-distancing. There aren't minds to sway here.