A) Most of the "Mac vs PC" ads focused on showcasing ways Apple products were superior to Microsoft ones [1]. This isn't universally true though [2]. Regardless, that strategy is better than showing people break dance with your tablets.
B) The "Scroogled" campaign has a different, more aggressive tone to it. The whimsical background music in the Apple ads don't come across as forcefully as the term "Scroogled" does. I suspect this tone is more off-putting.
[1] See some of the ads here: https://www.youtube.com/watch?v=C5z0Ia5jDt4 [2] https://www.youtube.com/watch?v=9DWLyrljLDk