But isn't that the same as people who argue because "they read it on a magazine/on the newspaper"? So they are wrong -- is it Wikipedia's fault though?

An encyclopedia is always the starting point, never the end of serious research. (It's ok however to stick to Wikipedia if a superficial acquaintance with the topic is enough!).

If there's something in a wikipedia article that experts will argue against, the article needs updating to be compatible with, even if does not include, expert-level knowledge.