If you're a startup competing against an open-source project, then this is potentially a great (not good) way to get a leg up. You get the benefit of access to the code until you don't need it anymore, then get the project shut down and reap the benefit of being the last man standing.
Sure, you might eventually run up against the license on the software you just lifted, but open-source projects can't afford the same protections that a well-funded startup has.
And if you somehow get sued for license violations, the penalties are usually more a slap on the wrist than an effective notice to knock that shit off.
I really hate the way my mind works some days.