Like I've said before, the waters between what's political and what's simply world events are pretty murky. I'm sure that just about anything can be turned INTO political. We could have another 9-11 and as soon as someone posts something that could even be deemed as political, the thread's going to disappear.
I don't know what happened with the Houston police officer thread, but I would think that illegal immigration and the problems caused by it would just be a world event issue that can be discussed without "R"s and "D"s attached.