Hydroxychloroquine (or Chloroquine) showed great early results in some prelim studies and some top international epidemiologists and field doctors were touting its success. So President Trump cautiously mentioned it as a promising treatment. The OrangeMan=Bad media and their allies, lost it -- and claimed:
- he was foisting unproven treatments on a gullible public
- leftist politicians restricted or banned it's use for COVID (even though it was proven harmless in 40 years of use)
- FakeNews outlets touted the dangers of it (and used a case where a wife murdered her partner with fish tank cleaner, as an example)
- and a few leftist scientists created junk studies to sabotage it's reputation.
It's sad the measure people will go either to prevent hope or to hurt Trump.
In the end, there are some studies that show it might help if used early in disease progression... and conflicting evidence that it helps/hurts later on. But that's not really the point -- the point was that when it was brought up, it was being touted by top epidemiologist in France, China and other countries -- and Trump was right to offer people hope that it was one of many potential treatments coming on line.
- Jan/Feb - Chinese, Italian Studies - highly effective in reducing severity/duration. (Best data at the time, since refuted)
- March - Original peer reviewed French Study (Didier Raoult) - highly effective in reducing severity/duration. (Best data at the time, since debated)
- July - Henry Ford Medical Group: Hydroxychloroquine lowered death rate. (OK data) 
- July - University of Minnesota - no effect on symptoms or severity (if issues early in hospitalization) w or w/o Zinc (Good data) 
- June - Oxford University study - no effect. 
- June - UK’s RECOVERY project: no difference in death, but worse on progression (if issues early in hospitalization). (Good data) 
The data is swaying me that the benefits of Hydroxychloroquine as a treatment are in question (but still unknown if it is a preventative -- however that seems unlikely). But that doesn't change that in March when Trump made his statements, it was the most promising treatment he had, and what he said was not even vaguely out of line with common sense -- and those attacking him for it, wanted people to die and the economy to collapse more than they wanted to give a political win to someone they despised.