Ifrit Jambe is literally spelled as Demon God Style Leg.
There is something called "Context",
Sanji's Leg Style when He taps into Ifrit Jambe is named after "Majin" which is Japanese Word for Jinn,
It does word for word translate to "Demon God", but that's like saying that Butterfly means Butter + Fly or Honeymoon means Honey + Moon,
No need to separate the words, it's Majin Style Leg - Ifrit,
Majin is Japanese Word for Jinn, and guess why Oda used it? Cuz Ifrit is a Jinn, He originates from Quran & Islamic Knowledge,
It's like Sanji is using Jinn Style, which Jinn? Ifrit,
Who's Ifrit? Every Muslim knows his Story, He is a Demon Servant of King (Also Prophet in Islam) Solomon,
Ifrit is not a Demonic Deity, He is Servant who told Solomon that He could bring the Throne (From another Kingdom) to him before He even stand up, and also Jinn are Beings made of Fire, hence why Ifrit fits Sanji,
Sanji is basically Luffy's Ifrit & that Style gives him Enhanced Flames & Speed,
No need to compare it to Luffy transforming into Sun God, and Zoro transforming into Asura,
Sanji instead transformed into Stealth Black (Eventually We both agree, He will change it to Sora instead),
Just like Franky turns into Franky Shogun, and Chopper turn into Monster Form, and Robin turn into Devil, and Usopp turn into King of Snipers,
Sanji is Warrior of Science, not Demon God.