My guess is it’s uttering phrases like
“I could of course be wrong…”
“We don’t know everything, scientists don’t know everything…”
“Scientists can be biased too…”
and so on.
Of course, some forms of intellectual humility (stating conclusions, correctly, in terms of probabilities or possibilities) are actually interpreted to go against your conclusions. See for example Gilberts interpretation of scientists using words like “may”, “might”, etc.
To some people who are just completely closed-minded, it doesn’t matter what you say or how you say it. If you’re not speaking in terms of absolute confidence, then you’re just guessing on no basis, and unsure of yourself and your conclusions. If you speak with confidence and assert things strongly, you’re being dogmatic, parroting the party line, and closed-minded, bla bla bla.