Nothing to stop you posting it in that topic.
There is no specific section/forum on security, just a topic and there is no rule saying that you must use it. Whilst posting in the topic you suggest would make it easier to find all security related items.
This 'Interesting' topic has been going for some considerable time (June 2007) and has a great deal of activity, so it is always high up the chronological list of the topics on the General forum. So for those regular forum browsers they would be likely to see the new activity as you and I obviously did.