As usual with late night US time questions, Monica beat me to an answer, and I agree with her. I do want to add something though.
I was wondering if questions like this have a chance, or have a tag "World building fails" or something. Maybe asking for better ways to do it, or just better answers than the ones provided.
That's not what tags are for at all. A tag is generally good if it reasonably fits in a statement like "I am an expert in tag-name". It might sound a little contrived with the exact tag name, but it shouldn't make you want to look at the person in question and ask "are you for real?". A good tag also should be usable as the single tag on a question. We are already stretching that by having the science-based, reality-check, fantasy-based, magic and so on tags. There is a certain precedent there, however; RPG has its rules-as-written, SO has the language-lawyer tag, and so on (both of those specific examples serve a purpose quite similar to our science-based in the context of their respective sites).
There is no reasonable way for a person to say with a straight face "I am an expert in world building failures" (okay, maybe there is, but it doesn't really mean what you are implying for the tag to mean). And it makes little sense as the only tag on a given question in terms of question categorization. Hence, it pretty much fails both criteria. That makes it a bad tag proposal.
Additionally, the two specific examples that you mention:
- a marine biologist grad student who made two statements that show the author misunderstands evolution AND Darwin.
- one character mentions that -25C = -87F and everyone is OK with that.
aren't worldbuilding questions. They are either background-facts checking failures on part of the author, or deliberate characterization. For example, maybe the grad student was made up with a flawed understanding of evolution, and the statement made is a reflection of that rather than the author's lack of understanding of the subject.
- Worldbuilding SE isn't an "anything goes" site. Our site scope is quite broad, but this site still isn't where you drop just about everything and the kitchen sink. Questions asked here should relate to worldbuilding and some things are explicitly off topic. Like...
- Character building as a topic is explicitly and specifically off topic. Character building questions tend to only be really useful to the person originally asking them, whereas we strive to create a resource useful not only in the moment but also for years to come. What is considered good and bad questions across the entire network pretty well reflects this.
For actual sciences questions about the real world around us, the other sciences sites quite possibly may be better fits than Worldbuilding. What Worldbuilding adds on top of sites like Physics, Biology, Astronomy, Space Exploration, Earth Science and the whole slew of others is essentially a place to ask the hypothetical questions that have no real counterpart in the sciences (most of the sciences sites tend to scoff at hypothetical questions or questions with preconditions that don't match our real world; consider What if the speed of light were 100 times higher? for just one example that almost certainly would be shot down at Physics), as well as perhaps the cross-disciplines questions. I still feel that just because a question can be shoehorned into worldbuilding doesn't mean it necessarily should be.