I consider myself one. I am definitely a cultural Christian, and I believe in the wisdom of Jesus’ teachings. I suspect, however, that I don’t believe in the exact same way that any particular little offshoot sect or flavor of Christianity does. There are an awful lot of them, and they’re often at each others’ throats - which makes me suspicious that any of them has all of the truth.
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.