It is very easy, they are using someone else’s name and brand without permission. If they don’t care about stealing a reputation, they probably won’t care about stealing others money either. And now they exit scammed.
It was a hack, and it's very stable now,
One thing you should know is that, most of these p2p platforms go through some difficulties at first, Localmonero did, localbitcoins did and that's what made them stand strong before they shutdown after years.
OpenMonero has been running for 12 months only, so it doesn't make much sense to shut down a profitable platform and exit scam with barely $20k.