Hmm, that's not quite fair.
There was a lot of negative impacts, especially in the wholesale colonisation by 'modern civilisations' against weaker or less developed neighbours but I was always surprised in Star Trek (except in Voyager where it seemed to happen a lot! eg the Kazon) that you never really had the other situation of less developed civilisations taking from more civilised ones. Sadly they usually want their weapons technology rather than their legal systems...
