You are absolutely correct.
The problem is about the efficacy of prophylaxis.
The mosquitos are adapting to CQ after 75 years and no longer used.
When I was in RVN they added one small white pill daily from (IIRC) one large pink pill a week for this problem.
A side note:
Distant kin that works in a hospital tested positive for Wu-flu, a few days into quarantine developed breathing problems. On admittance to the hospital was given CQ and put on oxygen. Released in a couple of days, more quarantine and just this week returned to work.
In this case I don’t care about mosquito’s and how well it treats malaria. I care about treating Covid 19. The point is that the flyer advertises Chloroquine as safe. And the Hydroxy version of it is even safer.