Eh warlock is technically an oath breaker. I would not let whomever is saying this upset you. They sound like they are confused as well.
Learning to use energy from the world around you is a good thing. If your draining from other people, some call it psychic vampirism. I personally feel it best to learn to take only what you need, from mother nature rather than people, as it has it's drawbacks.
Being open minded is also a good thing. Just don't let your brains dribble out ;)although magic can achieve a lot it does not make the impossible possible