The problem is, in most cases, historically the type of actions Shkreli tried often ends in disaster (often done by someone intentionally being malicious, I might add).

Shkreli may have been able to work his pseudo-Ponzi-ish scheme to investors' benefit. But it is pretty easy to look up the sordid history of the vast majority of Ponzi-type schemes, to see why this type of activity is generally illegal.