1. Not for coronaviruses.

2. They are known but they are by no means mild. A trial in Brazil just got aborted due to severe heart problems.

3. So does almost everything. If that's your threshold for taking a drug then I have a lot of homeopathic remedies to sell you!

4. Actually the doses given for COVID are often higher. Not sure what long-term has to do with anything.

5. That assumes that the risk of side effects is zero. It's not. Also, there is an opportunity cost to taking HCQ instead of something else.

I totally agree with you that we should do proper trials on this and see what happens. But right now there is zero evidence that it actually works, and some (admittedly low-quality) evidence that it might not.