Why does Dana Scully not believe in aliens or any of the other weirdness in the x-files?
Every week there's a new monster (MOTW) where all the evidence for outsiders disappears, or there's the mythology where the government is covering it up.
I'm a huge skeptic in almost everything, but if I saw what she saw, I would clearly believe. That's plenty of evidence for me, and I'm an actual scientist (well PhD engineer. I definitely did real science in school though)
The shit's clearly real in their universe.
(Sorry, just been watching the first season of the x-files for the past few weeks)
Just because you had aliens last week doesn't mean that you can have Bigfoot this week. Blurry photos and poorly substantiated ravings don't become good evidence of things until you get a lot more genre savvy.
And just because the thing you have matches Bigfoot on points one, five, and six doesn't necessarily mean it's going to be like Bigfoot on points two through four. Especially if there's not a unifying theory of Bigfootness behind them and they're just a list of aforesaid poorly substantiated ravings.