As pattar said, coaches aren't just scouting for those who have maxed out on their potential or who the best player is at that moment. They're projecting. They're looking at a good athlete or someone with physical tools and thinking about what they can be in the future.
You say they're uncoordinated, but maybe they just haven't been playing the sport long and they are either new to pitching or have had poor pitching instruction. A coach might see them and think "If my pitching coach works with her for a year, she's going to dominate our competition."
After all, if they're uncoordinated and pitching with poor mechanics and they're still throwing in the mid-50s, that sounds like two potential stars if the right coach gets hold of them. I'd be interested in, at the very least, talking to those players if I'm that HC.
Makes perfect sense, but for the fact that this school hasn't had a winning record in 4 years and is loaded with potential pitchers who can't seem to get it together.
Maybe just an anomaly.