Haiti desperately requesting outside help and potentially receiving it is neither "imperialism" nor "neocolonialism", particularly when such intervention comes from their Caribbean neighbors rather than distant foreign powers.
Addressing the comment about "stifling Haitian sovereignty": Haitian sovereignty has already effectively ceased to exist. Haiti is a failed state with a government consisting entirely of empty chairs and interim officeholders. It is completely unable to control either the gangs or mobs. The best they can manage is for police to control less than one fifth of the neighborhoods in Port-Au-Prince, and nothing anywhere else. The Haitian government only exists as a legal fiction at present, and does not exercise sovereignty over anything.
The Haitian ruling class is responsible for the gang problem in the first place, any outside intervention that involves restoring their rule rather than excluding them from power and rebuilding the country from the ground up is doomed to fail. Seeing as though there is little appetite for a long term presence the best option would be to encourage the formation of revolutionary organizations against the corrupt government instead.