It's the exact same ruling as Mesprit, Uxie and Azelf LA (and other similar cards) with Great Ball, Call for Family, Call Energy, and so on.
The Power clearly states that it has to be played from the hand ("When you put Giratina from your hand onto your bench"), when you use call, the card is moved directly from you deck to the bench, therefore, it is not played from the hand. This is a very basic ruling, the creators of those threads were wrong, so feel free to mention it when you see someone claiming this in another thread in the future.