You seem to be confusing a wiki with an urban dictionary.
There is no precision involved. There is no science to it. A wiki is unreliable because anyone can contribute. There is no foundation for accuracy. This "dynamic nature" has no bearing on improving or insuring accuracy. All contributions could be wrong in a given subject. All contributions could be by people associated with an agenda. There are no odds guaranteeing that the next contribution will be a correct one. Who determines what is accurate? Misunderstanding can come in waves / trends. Contributions can be random or organized. One ignorant person might have fun spending time contributing to a wiki.
As a reference wikis are best avoided. You might as well introduce the same info prefaced with "some say" or "some believe" but to use a wiki as a point of fact presents the info absent of credibility. It promotes a false conception to cite a wiki the same way a dictionary or encyclopedia is cited.
There is an entire generation who bases their perception of truth on how they observe usage. It does not matter whether the majority uses something incorrectly. It is very short sighted and frequently self-serving. It is convenient. They don't have to put effort into it. Their logic only goes as far as "I see it done this way all the time so that makes it correct." Yet you see people speeding everyday and that is still illegal.
When researchers first discovered the effects of warfarin, they actually thought that it DID thin the blood. The theory was that 'thicker' blood took a shorter time to clot, so anything that made it take longer for the clot to form must have 'thinned' the blood.
Once they got a better idea of how warfarin ACTUALLY worked, and that it had nothing to do with the viscosity of the blood, the term 'blood thinner' had become a common term describing what warfarin does.
Unfortunately, people use the term 'blood thinner' without really knowing how warfarin actually works. And they maintain this bias no matter hoe many times they're corrected or the actual process is explained.
Unfortunately, we're stuck with this error. Plus, if you say 'anticoagulant,' I'm not sure how many people will understand what that means.
I'll continue to say 'anticoagulant' and correct people (especially medical professionals who should know better) when I hear them say Blood Thinner, but I suspect that many health care professionals (like VitDoc) have an easier time telling patients 'blood thinner' - even if it's wrong - than to try to explain coagulation.