Happened to me too, long ago. Bought a beater bike for $25, test rode it, everything seemed ok until I shifted into the biggest cog. Destroyed the RD and bent the hanger badly but didn't break any spokes.
Not the manufacturers fault at all, this is a simple RD adjustment error. Low limit screw prevents the RD from going into the spokes like that. Of course, if the RD or hanger was bent after everything was setup then a failure like that could've occured.