You are wondering a lot of things it seems. There is a hidden message between my two posts, it was a question by a user that is now banned, so you can not see it. But I can.
And my 2nd post was a reply to that question.
As to why the system does not join automatically 2 posts by the same person, there is a time period when this is done, and if more than this time has gone by when the person makes another post (following another post made by himself), they are kept separate. Maybe you did not know this, so Im happy that you are learning a lot today.
What is spam and what is not is sometimes subjective, I would say that if something is only interesting for the person that posted the command, then it is spam for all the rest of the users.
Its like if I do !seen sexyAF it is probably not interesting for a lot of people.