Immorality of the oligarchs

I can’t help having my suspicions as far as Russia’s oligarchs are concerned. Khordokovsky, Abrahmovich et al made vast fortunes in a small amount of time by taking advantage of a muddled, fast changing society. By buying up extremely valuable stakes in state industries for virtually nothing they have enriched themselves greatly while fellow countrymen live in abject poverty.
Now, assuming they broke no laws - as the laws were fluid and perhaps ill-defined during the period - are these oligarchs any more guilty of immorality than multimillionaires who have made their fortunes in more stable systems?
Basically, they must have known they were taking advantage of a less-than-fair situation. Does the fact that they did make them immoral or does it make them shrewd businessmen? Or both?