We are all being told that while many are bound to criticize another intervention in Haiti, but this is the only feasible way forward in a very difficult situation.

Violence is rampant, and Port-au-Prince is overrun with feuding gangs that are murdering, kidnapping, and impeding the flow of humanitarian aid to the island. Progress on economic and political fronts is nearly impossible under these conditions, which existed even before Moïse’s death.

The key takeaway is "before Moïse’s death".
In October, the government of Ariel Henry, Haiti’s de facto prime minister and president, called for a foreign military intervention—“the immediate deployment of a specialized armed force, in sufficient quantity” to stop the street gangs that are terrorizing the population and cutting off access to Haiti’s ports.

The question is why Haiti keeps getting over-run by gangs and "require" U.S. intervention? To answer that you must first understand that these aren't gangs.

One thing is clear: the current paramilitaries, described in the mainstream press as “gangs,” must be analyzed on the historical continuum of U.S.-sponsored, state-affiliated armed groups, tasked with subduing the perennially “restless natives.” The preferred weapon of the mercenary gang bosses—Izo, Kempès, Barbecue, and others—is the torching of the communities they seek to subdue. Johnston points to the Michel Martelly administration (2011 - 2016) as being the first expression of the PHTK to use armed mercenaries to do their bidding.

Once you understand that these are actually private armies that are being used by Haiti's elites against political rivals, and that those same elites are the ones calling for yet another U.S. military intervention, it makes clear who stands to win and why U.S. marines will not/cannot fix anything.
So what can stop the humanitarian disaster there? Haitians can, just not those same wealthy elites.

Violence by armed gangs has fallen "drastically" since the emergence of a vigilante justice movement that has seen at least 160 suspected criminals killed in the last month, a report by local human rights research group CARDH said on Sunday...
The vigilante movement, known as "Bwa Kale", began after residents of the capital Port-au-Prince lynched and set fire to over a dozen suspected gang members in the early morning of April 24.

CARDH said "almost no" kidnappings had been recorded in the last month and counted 43 gang-linked murders, down from 146 in the first three weeks of April.

"Without making a value judgment, the 'Bwa Kale' movement has in just one month produced convincing, visible results; fear has changed sides," CARDH said in the report. "Both kidnappings and gang-related killings have fallen drastically."

That was just the start. Hundreds more of these paramilitaries have been killed by vigilantes since then. This might be a big reason why Haiti's elites have been so insistent on military intervention - they are losing.
Haiti still needs humanitarian help, but it doesn't need U.S. marines. I don't know if the gangs can be defeated by Haitian vigilantes, but maybe we should wait and see.