Building organizations is usually easier than fixing them if the things that need fixing are deep power structures and there's no impetus from within them to overhaul. You could spend your entire life trying to reform an organization "from within" and fail simply because those structures would rather maintain themselves than do anything else. The methods and reformability of an organization are what actually happens, not what they say they are. For example, from members of a different org, I learned they would get routinely harassed as individuals for all of their personal decisions and social media posts, by leadership, based on sweeping false declarations by leadership about how Maoist political criticism works and is beneficial. Rather than reform, that org kept all of its same leadership and bad practices because everyone who recognized the issue left rather than spend their time trying to organize against the leading and founding clique in their organization. Time that was already taking up more headspace, energy, and discussion time than actually doing any org programming. Org programming that was itself not particularly deliberated, let alone criticized, as it was introduced by that head clique and criticizing it meant facing personal rebuke in public.

The only thing that isn't easier when building organizations is actually doing it very well, as it means accounting for a thousand different things. This is why the best builders were already members of orgs that were most of the way there but needed changes. The practices are ingrained and can be reproduced with good modifications.