Why do Wikipedians hate the protection of intellectual property?

"Hate" may be too strong a word, but the simple fact is, nobody likes being inconvenienced by a government's attempts to protect someone else's property (unless that someone else is paying them, or something like that). Wikipedia merely reflects this simple fact, since nobody on Wikipedia owns much of anything, including the content they themselves create for it. (Assuming they didn't steal that from someone else.)

It's more difficult to protect intellectual property anyway, because it's so easy to copy, and copyright warnings are so easily ignored. Private entities that could otherwise protect *physical* property with locked doors and armed guards don't have many good options with intellectual property, so they're compelled to ask for government help. Again, nobody likes it, but the alternative could very easily be much worse for society as a whole.

Last but not least, while it's true that most of the people who would benefit from laws like SOPA (in the US) and the one proposed in Spain are wealthy corporate types, it's hardly inconceivable that such laws could protect ordinary people too, such as independent musicians, writers, software engineers, and visual artists, assuming any of those people know a good lawyer.

(See also TL;DR list at bottom.)

Wikipedians do not, as a group, hate the protection of intellectual property. Your assertions seem to constitute a straw-man attack on Wikipedians.

Many Wikipedians do object to certain proposed laws because of secondary effects of those laws. For example, in the U.S., the proposed Stop Online Piracy Act (SOPA) is obviously intended to combat online piracy. While it would have the effect of inhibiting piracy (but only slightly; there are many workarounds), it would also have the highly undesirable effect of making websites—operating in good faith—subject to potential shutdown if a single one of their users places a copyright violation on the site. This is why many Web users, and large Web companies including Google, Yahoo!, and eBay, object to the proposed law: SOPA would have dire ramifications for any web resource hosting any kind of user-generated content.

Your example is of a Wikipedian objecting to a similar law, presumably for similar reasons. While these laws may have rational goals, they are rather misguided in their implementation: they offer fairly few benefits (piracy will, unfortunately, continue despite the law) while exposing websites with any kind of user-generated content to game-changing levels of risk. Many websites and systems that have flourished under the Digital Millennium Copyright Act (DMCA) "notice and take-down" system would be untenable under SOPA, including among others YouTube, Tumblr, blogging sites, and, to some extent, Wikipedia. Ironically, Wikipedia would be better off than many of these sites because it has a level of active filtering against copyright violation: many websites filter only passively; that is, when notified of a violation. In fact, Wikipedians often mistakenly delete copyrighted content posted by the owner of the copyright simply because it is not sufficiently clear that there is not a copyright violation!

Don't mistake "hating" a particular instance of a law for hating a general concept. Wikipedia actually actively uses copyright law: the Creative Commons license that it uses for content is, after all, a copyright license—albeit one that manipulates copyright so as to facilitate reuse while enforcing only attribution and the continuation of the license.

I get the vague sense from my past interactions with you that this is simply trolling, to somehow call Wikipedians pirates. As I've established in this answer:

a) Wikipedians do not hate the protection of intellectual property; accusing them of such based on their objection to a particular copyright law is a straw-man attack.

b) It is entirely legitimate to object to a proposed copyright law, especially when that law has bad side-effects and/or is ineffective.

c) Wikipedians do more than many websites to ensure the enforcement of copyright, and in fact use copyright law via the Creative Commons licenses to enforce the freedoms allowed of their content.

Because the copyright system is screwed up.

Restrictions on the internet does nothing for the average person, it actually hurts us. The only people that gain anything from it are the people who actually run corporations.