Do Muslims really not know that this stuff exists?? It's like the hadith "Whoever among you changes his religion, kill him." Bukhari
At the moment, I am finding that this hadith is half authentic.
"'Do not punish anybody with Allah's punishment (fire).' I would have killed them according to the statement of Allah's Apostle, 'Whoever changed his Islamic religion, then kill him.'"
The second sentence is fake because it contradicts the quran, and not all hadiths are authentic, and islam is peace.
The first sentence is legit, because it is sahih bukhari, and islam is peace, and it proves that ISIS are not even Muslims.