I'm not a lawyer, but I would think that there are significant differences between hosting copyright violating material, and hosting potentially patent-infringing material. It is much easier to unintentionally violate some patent claim.
If someone uploads something copyright-violating to the repo (e.g. some nintendo ROMs without nintendo's approval), they have to lie when filling out the upload form, because that form makes you declare that "You will not upload or share any content that you do not have the legal right to." If somebody uploads something copyright-violating to the repo, it will be removed as soon as it is found out that that happened - it is pretty straightforward to check the copyright status of something.
Patent violations are different, because it's much less clear cut what it means to violate a patent claim. There are hundreds, even thousands of patents that might be violated by, for example, the Linux kernel. Does that stop us from distributing it? Of course not.
In the case of something rather specific like a codec, it's easier to check that some code might actually violate that patent in some countries. But it's still up to a court to decide whether the patent is actually violated, and it's still up to the patent holder to identify and sue the one who is violating their patent. And they should go after the original source of the patent violation, and target the distributors only after it has been established that there is in fact a patent violation.
In the case of MP3, there are a lot of patent claims, but so far they have not enforced license fees on FOSS mp3 decoders.
So as a rule of thumb, I would say: take copyright violations seriously, but ignore software patent claims. Copyright and patents are really very different things. I don't think German courts even allow software patents nowadays (
http://en.wikipedia.org/wiki/Software_patents_under_the_European_Patent_Convention#Germany).