Given that Chroloquine has been around for a long time and that it is well studied, is there any merit to assume that using it was not a random idea and that it works against some other known RNA viruses?
It is know to be a zinc ionophore so I would not call it random. That said, it is known to have some side effects. [1] My concern around its use is that it requires a prescription. People won't likely be using this until a doctor prescribes it. By the time a person has gone to a doctor, the virus has likely already replicated quite extensively. Zinc ionophores would be most beneficial if taken very early on after initial infection.
[0]: https://www.jqknews.com/news/388543-The_novel_coronavirus_pn...