The main problem is a bit like with paracetamol (for other reasons) - paracetamol perfectly safe at small doses (say up to 3 grams per day), but letal at 20+ grams per day (OK, N-acetylcysteine has a good chance to help you there). Higher doses of chloroquine interfere with your internal pacemaker in many ways.
That is one of the issues with Raoult's study (there are many others): there are many (justified) exclusions to begin with for all kinds of risk factors. Fair enough, but there is a bit of overlap with those risk factors and the risk of death anyway, and risk of death of COVID. That is essentially preselecting patients in better shape in the chloroquine group, to begin with.
Then, it is very different from popping a pill as prevention or blind treatment of possible symptoms.
And yes, doctors all over the world have been trying hydroxychloroquine without miraculous results and with some incidents/deaths.
It is not a magic bullet.
And since we love graphs here, this is - potentially - your heart on an excessive dose of chloroquine (or if you have risk factors)
https://en.wikipedia.org/wiki/Torsades_de_pointes#/media/File:Torsades_de_Pointes_TdP.png