I think you've missed the basic principle here.
Is the word "doorknob" an insulting or offensive word? No. Is the phrase "You absolute doorknob" something directed at another user as an insult? Yes.
For clarity, if you were to do that on GTPlanet, you'd get your post removed or edited and find a notification in your alerts telling you not to do that again or a warning from the staff - whether or not anyone reported it.
Again, you cannot be surprised when sending insulting messages to other people that, should they (or anyone else) report them, you get action taken against you.
It's also worth noting that the - entirely human - PSN moderation staff, who are not specialists in any one game, will look at messages sent before and after the reported message too.
Question, to which honestly don't know the answer and I'd like to hear your opinion, or fact with proof:
Is saying "dirty driver", or "you drive dirty", an insult?
That's the basic principle I'm looking at. Because as a 40 year old man I never, ever, thought of "dirty driver" as an insult. Just like I never thought of other words like "cheater" to be an insult.
Will Playstation staff suspend someone for simply saying "cheater"?
Why am insisting on the word "dirty"? Because I saw it happen (not to me though): someone wrote it, with nothing else (no sentence, no player tagged) and it got deleted from the chat history in the GT7 lobby. Which means it got reported and someone got a warning for it.
Anybody on this forum can make the same mistake in the GT7 chat and get reported for it, if the player doesn't know.
Something similar applies to the word "down". IIRC you can't even type it in the GT7 chat. Yes, we know why it is censored, but not allowing players to write something as simple as "hey, look down" is laughable. The message is automatically denied.