I mean if they're going to act (or rather, seem) malicious then they might as steal the backed assets they have right now rather than hope to pump-and-dump enough to make more money. It's not like either is more legal than the other.
Just arbitraging ensures this scheme never blows up in their faces and they can never get charged with a crime. Acting shady (but not actually stealing anything) isn't illegal.
If your ability to make money off something is based on a pump-and-dump (or more fittingly, dump-and-pump) scheme, then you are either committing securities fraud or ending up in a lengthy legal battle over securities fraud.