Why do people hate Wikipedia?

Wikipedia is a site where anybody can edit, broadly speaking, any page. With this power in anybody's hands, many things can happen to perfectly good information / empty pages.

True facts can be extended, or deleted in general. Some people enjoy malicious editing, and will purposely alter information to cause chaos, or achieve another malicious effect.

Even without any malicious intent, false information can be posted about a topic without the user knowing that the information is incorrect. Layouts and formats have been provided, so then users are highly encouraged to cite sources - however, many do not follow this layout.

In a nutshell, anybody can edit it - and although some people like to build up on something so grand and make the world more knowledgeable, there are people who like to strike chaos and give false information.

There are also those with admin rights who like to throw their weight around and repeatedly delete my efforts at adding a page for no reason whatsoever...in a democracy there is a discussion before those appointed with custodianship take action, in wikipedia land, it's just a collection of dictators...

Another problem with wikipedia is what I call "wikipedian information" which is place to espouse certain views without regard to historical or scientific fact (just look at the article on leucism which is replete with falsehoods and misinformation). I have tried numerous times to add valid information from peer reviewed sources only to have them deleted by someone that originally posted the article, because the research I quoted did not support their view.

Essentially many articles are guarded by quite territorial people and any new information or corrections added by others may be deleted by them when they get alerts that their article has been edited. This repeatedly happens over and over again. My own students have used wikipedia to write reports and wound up failing the assignment because the information was blatantly wrong.