I don't mind someone having a footer link trying to sell something (reasonably related to this forum), if the main posts always shows an obvious intent to bring content to a thread.

But I do agree that a number of the posts are basically one-liners that seems very much to have been made just to be able to bring in the link in the thread.

When the posts don't try to bring value to the thread, then it isn't wrong to call them out as spam.