So far as I can tell, most of them did not even stop to ask whether there was a non-racist explanation for those tweets.
I'm trying to figure out if you are expecting them to ask you personally or if it fits your criteria for them to stop to ask someone else, such as their roommate or cat.
Does such an approach strike you as due consideration?
I leave the measure of what is due to the person making the claim. How much consideration would you suggest in this situation to be "due" and how is that determined?
They seem to have satisfied themselves. Is there some obvious indication that they regret their posts as overly hasty or bemoan that in hindsight their consideration was deficient?