Depends on how specific you want to be. I think "stupidity" is a very accurate macro statement on the situation, when viewed over time and scale. Note also in the video that Bonhoeffer went into detail explaining that these "stupid" people effectively give up what independence they had in favor of group think and trite statements from authorities. That's rather more detailed that just "stupid", and it's very true of the covid world today.
I agree, "stupidity" can be a very accurate term to refer to the situation in general. What was crossing my mind while writing my post was more the thinking errors I have made many times when judging some situation around me. Sometimes one can judge a situation too lightly by observing this "stupid" behavior, when in reality perhaps the situation deserves some slightly more thoughtful consideration. A trivial example: I am driving my car and in front of me there is another vehicle in the middle of the street, driving slowly and without letting anyone pass; the driver could well be an absolutely inconsiderate individual who cares very little if someone is behind or if they want to pass him, or a person who is just learning to drive and still does it with some insecurity, or an elderly person who has lost reflexes and driving skills over the years, or any other case that one can think of. I don't know, maybe it's because of the derogatory connotation of the word "stupidity", but although the behavior could rightly be called stupid, at least IMO it doesn't seem fair to me to judge all these cases as just "stupidity" (although I certainly did it several times ).
To put it more simply: while I agree with most of what has been said here about "stupidity", at least on a personal level, I prefer not to abuse the use of this "label" because I feel it could sometimes desensitize or lead to being inconsiderate, which in fact has happened to me.