No, IMO, he slammed her because she was up to the usual media tactic of slanting the news - in this case, showing tight shots of his book signing rather than a wide angle of the crowd. Had she shown that as well, instead of trying to minimize the size of the turnout, it would have been OK.
I'm sure you are aware of this tactic, which rightly came under fire.
It was a book signing, not a campaign rally. Have you seen coverage of book signings held by other politicians (or celebrities, for that matter)? They're typically always covered with relatively tight angles, because the structure of the events are not really conducive to wide-angle shots. Trump's event was covered like any similar event would have been, but that wasn't enough for him. Trump wanted CNN to promote his YUUUUGE crowds, and is complaining like a petulant child because they didn't do it.