considering all the terrorists attacks from Isis , Turkey had to face recently, one should rather wonder why they didn't do it earlier.
Also, Syria won't probably exist (divided among Kurd and other group) anymore once it is over; so Turkey has also to protect itself against a future kurd state and/or prevent it to happening... so it is their best move
(lol the messiah is coming from Crimea... yeah right... guess the death toll wasn't high enough for him to come in the XX century)