My sister in law knows how to explain it way better than me, but this is what I remember from what she explained. (I questioned the near kisses in the lakorns, and the camera angles after watching Sawan Biang).
So back when Sawan Biang aired it was super extra with the forced kisses and the bedroom (rape) scenes. After that the elders, then made a decision to have only one kiss (someone correct me if I'm wrong, I'll ask my sis in law later) per lakorn. The actors had to go then have more near kisses, the sniffing kisses, and more conservative displays of affection.
Don't get me wrong for those rape scenes I am all for less, but it also took with it the willing scenes as well.
Anyways the elders set up all these rules and censures that are still standing since then. It was to not givae bad examples to the youth watching and could be influenced by the lakorns. (Laughable at the time, but also understandable due to what kids copy and what influences them. Not all but it happens)
All other channels are less strict about kisses and bed scenes.
I have been hoping they lift it up somewhat since a few lakorns have more kissing scenes now, and rather steamy scenes between leads and side characters.
Maybe for this they will allow Matt and Nadech to lock lips, and have as much skinship (those sweet hugs) as possible.