Ramblings

Science isn't a living person. If anything they mean “scientists say”, and even scientists more often than not will not say things. A scientist is a person who tests falsifiable hypotheses in experiments that adhere to the scientific method. These experiments will lead to observations, and these observations are basically data. Data, even less so than scientists, will definitely not say things, and it definitely does not mean things. Data is not causality, and it rarely is correlation. It takes knowledge and context and understanding of a field to properly assess that data to draw conclusions. Rarely does the data speak for itself. “Science” in this context is misused by people who do not understand the science to appeal to authority. Especially younger, impressionable demographics are vulnerable to “science”, because in an unreflected mind “science” is the one and only¹⁾ and when science says so then it must be true, even if science never said anything.

More often than not, the “conclusions” drawn from presented studies or general research papers are a little bit more… enthusiastic than what the paper actually suggests. In the case of the DEFCON video “DEFCON scares me an science says it will scare you too” the premise is that “science” found something inherently and uniquely “scary” in DEFCON that affects everyone equally. Depending on how you want to see it, either you accept that the concept of fucking dying is perhaps a little bit disconcerting to humans (which is not new or something that needed science to verify) OR you say that there is no one such thing that every human ever will definitely always respond to with fear (ie. getting scared), but either way you will have to agree that this is NOT what the study said. The relevant study here is named “Education from inside the bunker: Examining the effect of Defcon, a nuclear warfare simulation game, on nuclear attitudes and critical reflection.”²⁾ and, as is already apparent, does not actually study emotional response to the video game DEFCON and instead examined how, in people, the perception of “nuclear attitudes” changed after playing DEFCON. TL;DR: Most people after playing DEFCON took the threat of nuclear war more seriously than before playing DEFCON, in comparison to those who did not play it.
The science does not necessarily contradict the claim of the video title, but it's clear that the science, apart from not saying much at all, definitely did NOT say what the designer of the video wanted it to say.
In its most fundamental sense, “Science says” is often used fallaciously by taking studies, finding in them data that points in some direction, and then going on to claim that study has established “facts” in that direction even though the science has, if anything, only ever pointed in that direction. It makes for some good headlines, though.

To be fair, saying “science says” isn’t always completely off. Science does overwhelmingly support that climate change is real, that the earth is billions of years old or that vaccines work. But even then, it’s a shorthand that glosses over the actual work - the experiments, peer review, debate, and refinement that make those claims strong. Scientists don’t publish papers titled “hello, I am science and here’s the truth“. They build evidence that, over time, becomes very difficult to deny. The phrase “science says” is popular not in labs but in clickbait, political speeches, and advertising, because it carries weight without requiring people to engage with the details.

Science isn’t about parroting authority. It’s about doing the work, testing, failing, refining, and questioning. So when the best someone can offer is “but science says”, it’s usually a signal they don’t actually understand the science well enough to argue from it.