Well, I would agree with you at least that some Christians are too quick to blame things on demons. If you are tempted to sin, chances are better that it is your own sinful nature tempting you rather than a demon. If you have some physical malady, chances are that it is a medical problem rather than a demon.
However, the Bible does tell us that demons are real entities and not just some metaphorical thing, so I wouldn’t dismiss them out of hand. One thing to consider is, if there are demons looking to influence us, and you discount their existence completely, then you will of course never be on guard against that possibility.
When I was in high school we had a charming Asian Studies teacher who gave us a survey of Buddhism, Hinduism, Asian culture and literature. We were naturally curious about his own religion, and when we asked what it was, he said, “I’m a Neo Zoroastrian’; and he didn’t elaborate.
I think from now on that’s what I’m going to answer, whenever someone asks me the baited question, ‘Are you a Christian?” It’s about as meaningful an answer as the intent behind the question usually is.