* Because higher capital inflows and outflows correlate to the frequency and severity of financial crises.
This is pretty much like saying that abolishing the privileges of aristocracy and clergy would have reduced everybody status. It was only true from the point of view of someone holding a title.
Our current Western wealth and working condition are the result of centuries of colonialism and exploitation for the rest of the world which continues to this day. The only reason you could technically afford to buy clothing wear them once and then discard them is because they are effectively produced by slave labor somewhere out of sight.
If capital controls benefitted ex colonies the IMF wouldn't threaten to withhold western investment from democratically elected governments if they didn't eliminate them.