Some troll could just as easily jump out from under the bridge and demand a hundred billion dollars for a patent on Safari. Sure, and that kind of stuff

Some troll could just as easily jump out from under the bridge and demand a hundred billion dollars for a patent on Safari. Sure, and that kind of stuff does happen. And Apple likely makes decisions based on limiting their liability to that kind of thing. They have publicly stated that they objected to Ogg Theora because they had a patent license for H.264, and didn't think it was worth the risk to ship something like Ogg Theora, which may be covered by unknown patents. Now, H.264 may be covered by unknown patents as well. But based on the existence of the MPEG-LA and its patent pool, and the fact that they'd already invested in and exposed to any potential H.264 risk, they felt like there would be more risk to them to add Ogg Theora support than just sticking with H.264. Were they right? Who knows. But that is the decision they made. Now, we are just speculating about why they hate the GPLv3 so much. But they obviously do, and they have both done a lot to use their own patents offensively, as well as being cautious about infringing patents as a defensive stance, so my best guess is that the patent clause is their concern. But there's no way for me to be sure; there's not much point in continuing to discuss it, because it's Apple that has made this decision, not me. I'm perfectly happy shipping GPLv3 covered software; if you want to know why Apple isn't, you could try asking them, though are unlikely to get an answer.