Hogwash.
Nobody has been talking about taking it for years.
Just for a few months until the virus fades.
The same way the drug has been used for the past seventy years.
When I was in the Marine Corps we took it when we were going someplace with Malaria (such as the Philippines) and then stopped taking it when we went back to the United States where Malaria isn’t a problem.
Trump is like a general trying to win a war. He has to employ whatever weapons are available to him NOW. Waiting for the perfect weapon to be developed and delivered at the perfect time is not an option. If something is available that can be used in the short run, with minimal apparent risk, he must use it to defeat the enemy as quickly as possible.
Real world solutions are not always perfect or optimal. The theorists and bureaucrats are never on the front lines.