i think that imperialists through study of imperialism throughout history have learned that one of the most effective tools to contain a threat to imperialism is to control parts of the opposition.

this means that when there is a legitimate struggle going on, that it is infiltrated or engaged. for example - the "pirates" in somalia are probably very legitimate in their attempts to fight against nuclear waste dumping and attempt to protect fishing rights. true - some have probably gotten greedy and this is the focus of the media (of course). but - what happens is that something violent will happen - something that is enough to justify further intervention by the imperialists - and history has shown that these violent acts are sometimes the act of the infiltrating elements. we only need to look at incidents in iraq to see this example played out over and over again.

as GMAN pointed out - in general the "pirates" have been relatively peaceful. but an escalation of the situation would be the justification necessary for intervention.

another example - at some of the imperialist meetings of NATO, World Bank, G20, WTO - there was a segment of "anarchists" who were violent whereas a majority of the protestors were peaceful. some of the "anarchists" were likely infiltrators hired to delegitimize the protestors. perception is everything.