Do you mean the official Launch HNs for YC startups? They are indeed a special case, but not in the sense you describe. They don't get to happen multiple times in a year. In fact, each YC startup only ever gets one in its entire lifetime.*
Launch HNs do get special treatment in that we place them on HN's front page. This is one of three things that HN gives back to YC in exchange for funding it—those things are all clearly listed at https://news.ycombinator.com/newsfaq.html#yc.
Btw, don't be sorry! We want everyone to know how this stuff works, and we want it to be clear what the principles are (and that there are principles). Other than the three things I just mentioned, YC startups don't get preferential treatment on HN. They have to struggle for attention just like everyone else, and with the exception of a few community darlings, they find it just as tough going as everyone else, and aren't particularly happy about it.
* although I think I'm going to make an exception next week for a startup that did the very first Launch HN 5 years ago and is still kicking.