You have to analyse at the population here; capital controls are useful for preventing people who have accumulated sizeable asset holdings in country X from moving them to a jurisdiction Y where there are effectively no taxes. Of course this reduces the freedom of the people who control these assets, but there is a common fallacy (usually introduced by the very same people) where they claim that liberty (in the abstract, without the very important qualification that this is _their_ liberty) is being surpressed while not noting the very important fact that _they are the most powerful members of society_ and that preventing them from moving their assets means that a whole lot of good (social welfare) cna be done for other people, without substantially impacting the material qualiy of their lives (the wealth/"improves my life" is pretty logarithmic IME, e.g. moving from 20,000 EUR -> 30,000 EUR of income a year makes a huge difference, moving from 30,000 EUR -> 130,000 EUR still makes a big difference, but 130,000 EUR -> 1 million EUR probably does not bring a concomitant increase in happiness).

I think this quote from Paulo Freire is pertinent

> The former oppressors do not feel liberated [once the people with less power than them are given more]. On the contrary, they genuinely consider themselves to be oppressed. Conditioned by the experience of oppressing others, any situation other than their former seems to them like oppression. Formerly, they could eat, dress, wear shoes, be educated, travel, and hear Beethoven; while millions did not eat, had no clothes or shoes, neither studied nor travelled, much less listened to Beethoven. Any restriction on this way of life, in the name of the rights of the community, appears to the former oppressors as a profound violation of their individual rights – although they had no respect for the millions who suffered and died of hunger, pain, sorrow, and despair. For the oppressors, 'human beings' refers only to themselves; other people are 'things'.