Such rules aren't posted in the forum rules list, as such there should be a warning via note to the poster to allow the correction of the behavior before closing the thread. That's just common courtesy.
"You could make a new thread IF it were focused on custom content for commissioners."
As the title of the tread said I was offering custom content in the form of sketches and/ speed paint busts, if people bought something from my stores. This is an unusual form of "commission" but never the less people would be paying me and getting custom art, as such it is commissioning and not just advertising. The new content is in the form of promotions (which artists do as well). If you tell me this should be done in a new thread each time, I can accept that. If you tell me this can't be done then I'll have to say that, to be fair, you'll have to close a lot of other threads and not only mine (just to prove your friend right).