Yes, it seems unlikely that this was the only time the captain disregarded the sterile cockpit rule. (But I guess we'll never know)

GP:

> > It does not imply they are mentally unfit for captaining

It does, if they do it during the sterile cockpit periods.

You could also argue that sexist and racist ideas indicate that that person is a bit dumb. Which isn't what you'd want to see in a pilot

There have been some very smart racists in the past. Depending on your definition of racism, it could even include Nobel prize winners from the last century.

Yes, still, I think the average intelligence is lower (among people with racist ideas), although there are exceptions