Facing any circumstances, I would not eat a dead person’s heart, would you?
I believe that this person had gene of cannibalism and showed that trait facing the situation.
Probably Allah is trying to guide Muslim that who Sufiyani could be in Syrian war (not just one person but one of the two sides in war) … remember, ‘Hind bint Utbah’ the wife of Sufiyan … (or Sufiyani) … who did the same at battle of Uhad, ate the heart of her enemy Hazrat Hamza (RA).
Hind bint Utbah showed the gene of cannibalism because she saw what happened to her bellowed family members in battle of Badr about whom she was most proud.
Battle of Badr started with 3 one-to-one duel combat. From Quraish side, Hinda (or Sufiyani) father Utbah ibn Rabah, her uncle Sheeba ibn Rabah and her brother Walid ibn Utbah came out.
On Muslim side it was uncle of Prophet (SAW) … Hamza (RA), cousin brother of Prophet (SAW) … Ali (RA), and another cousin brother of prophet (SAW) … Ubaydah (RA) ibn Harith came out.
Battle started with Hamza (RA) killing his opponent Utbah in no time … Ali (RA) killing his opponent Walid in no time … but Ubaydah (RA) getting injured by Sheebah but Hamza (RA) and Ali (RA) free from their duel combat … moved-in and killed Sheebah. [Later Ubaydah (RA) died due to the injury].
Hinda was seeing all this … all happened in front of her eye … when she saw proud warriors of Quraish and ‘her closest family members who were pride of her too’ ending in dust…. So you can say that definitely her state was not normal when she ate heart of Hamza (RA) in Ghazwa-e-Uhad when she got the opportunity … just like this present cannibal (as you mentioned) did … under the state of mind similar to Sufiyani (Hind) after losing his family members to Syrian army (only difference is that many lost their family member to Syrian army or rebels, but none have shown sign of cannibalism).
It is evident that both (cannibal of Syria and Hind bint Utbah) share gene of cannibalism … who knows, present cannibal of Syria may have got his gene coming directly from Sufiyani … or Hind bint Utbah bin Rabah … and his action is signal from Allah for Muslims to recognise present day ‘Sufiyani’ … (remember, sign of Allah is always as subtle as this … and only few may get it).
Basharul-Asad may be bad … though under Hafiz-ul-Asad and Bashar-ul-Asad Syrians seen harmony, progress and good worldly life (even though Syria is poor country, living standard in Syria was better than most Arab countries … even better than some oil rich countries)… nevertheless both Asads are neither Najdis nor follower of Najd, when it is prediction of Prophet (SAW) as mentioned in various hadith books that evil would appear from Najd and today we are seeing the evil of Najd all over Muslim world by them directly (petro-dollars) or through their followers (fed by petro-dollars). Cannibal of Syria is also one of the followers of Najd, promoting Najdi value and war of Najd in Syria.