Get a young engineering professor talking and you might be quite shocked at some of their beliefs.
I think this sums up the error in your thinking regarding science. The views of young engineering professors about gender, or of academics saying gender is a social construct, are not ‘science.’ Science, as you so rightly say, is arrived at by the scientific method. This includes observation, experimentation, prediction, and, importantly, inference. Inference is not ‘proof’, nor is it undeniably “true”, nor is it irrefutable. (Some would say that the entire essence of a scientific truth is that it must be, at least in principle, refutable). And there’s the rub. Whether a scientific conclusion is '“science” or not is a question of general acceptance.
However, I think we are arguing at cross-purposes here. You used the word ‘proof’ earlier, and now the word ‘truth’. I fear you are equating “Science” with “Truth”, which is deeply, fundamentally, philosophically and scientifically incorrect. While in general terms we may think of many scientific ideas as ‘true’, we must not confuse the two terms. “Science” is a model, a human construct designed to explain the universe as accurately as we can. The heliocentric model of the solar system, and the idea that maggots sprang spontaneously from decomposing material, were both scientific, and constituted “scientific truths” in their time. They were arrived at by observation and experimentation and all the rest, and generally agreed upon. Improved observation, experimentation and so on, demonstrated that they were wrong, and improved explanations were arrived at. Real “Truth”, of course, is genuine, objective, and unchangeable. “Science” (or, confusingly “scientific truth”) is a human construct, and really does depend on “a sort of democratic majority of scientists”. I doubt very much if any genuine scientists would deny that.