Like many effective pharma, this one has side effects in some people. Among those people, some side effects are minor, for some are major and not recommended
The critics have effectively conceded that it is effective. Their argument rests on the fact that side effects are major and not recommended for everyone for that reason, which virtually everyone agrees with.
The phrasing of the critics obfuscates the issue, probably on purpose.
The side effects for taking 400 mg twice a day for 5 days are complete BS; tens of millions have taken more and for longer for malaria since the mid-1950’s, and at least hundreds of thousands of Lupus and RA victims have been taking it for years or decades. My own mother has been on it for 5 years while having cardiac affib as a pre-existing condition- with NO side effects at all.
If hydroxychloroquine was dangerous, we would have found out 50 years ago and it wouldn’t be on the market.