They are both basically saying the same thing. A is using "would not". B is using "do not".

I call "would(n't)" the modal of imagining. You're using a hypothetical situation. Yes, we even use "I would like..." when asking for things because it's less direct and therefore sounds much more polite. When you use "I (don't) want..." you are stating a fact in reality. You're pretty sure about your feelings.