If they existed they would be. The Judeo-Christian god does preach against those who use magic. And warlocks don't only use magic, they are a symbol of power for pagan religions. So yes, if god existed, and warlocks had any real magic, then yes, they would be enemies of god.
To me, it is absurd to claim that sorcerers are enemies of God. Just because the Bible condemns magic and sorcery doesn't make it true. It's not the power that counts, it's how you use it. I argue that a sorcerer's magical power is God-given in the first place. If God created all things, then he made sorcerers mystical. It was man who decided that magic is sinful.
Now I'm a 18 year old kid and please don't get offended. As a witch we believe in a god and a goddess. Now magic is not evil at all( go research please). There is no such thing as black magic. They are not the symbol of pagan religions. Oh and your a complete idiot.