As a faculty member, I totally agree. It takes far, far longer to grade a paper that is "different" or one that is on a topic unfamiliar to me than it does to grade a standard paper on a familiar topic. When I am grading a couple dozen papers (while also juggling preparing classes, writing and grading tests, etc.) -- I need to be fast and efficient with my time.
I don't read student papers to be entertained -- or to be educated. I read the papers to assess whether the student has demonstrated the mastery of the skills the student was supposed to learn. It's far easier to do that if I am familiar with the topic and can see at a glance whether or not the student has surveyed the literature properly, come to reasonable conclusions, etc. If I am unfamiliar with the topic, I may have to do some extra research myself to educate myself so that I can adequately assess the student's work. That takes extra time -- time I don't have.
I do give some students the freedom to be creative with some of their projects -- but only if the student is an "A" student and they have indicate a real interest in the special project they want to do. As the OP doesn't have a special interest in a particular topic, I would suggest he/she focus on impressing the teacher by doing a great job with a conventional topic rather than cause extra work for the probably overworked and underpaid teacher by choosing a more risky topic.