1. None of this list matters, cause you will kill yourself with work and other things before you get to med school.
Nonsense. It's completely possible to take a rigorous course load in college and still have time to do outside activities. In fact, you will likely have more free time during college than you will ever have during the rest of your adult life until you retire. It's also completely possible to be in medical school and still have time to do outside activities, although granted that you will be busier at some times than others.
2. While still having to take a ton of incredibly hard classes...You won't cover many of the health profession prereqs...Making your schedule that much heavier...but then you STILL have to schedule in your medieval studies class...Scheduling and your schedule will be a NIGHTMARE (see #1)
Again, not the big problem you're making it out to be, especially if you attend a medium-sized or large U where there are multiple sections of all the intro classes. I went to a small liberal arts college with only one section of each class, and I still managed to take one or two humanities classes every semester along with my science classes. (I was a natural sciences and Spanish double major.) Also, taking summer classes is always an option if you can't fit the classes in during the regular semester.
3. You won't cover much of what is on the health profession admission tests in the majors (DAT/MCAT/PCAT etc..) (see #1)
Not a problem. These tests cover only basic, freshman and sophomore level science knowledge, including intro biology, chemistry, organic chemistry, physics, and for the PCAT, calculus. Upper level science courses like genetics or biochem may be helpful, but are absolutely not required.
4. You won't be preparing yourself for any professional school classes (directly anyway) (see #1)
My friend, very little that you take in college will prepare you for any professional school classes--unless you are somehow able to take classes along with the professional students. But that's ok, because the purpose of going to college is not to prepare you for professional school. It's to prepare you to be an educated, well-rounded person who understands that there is more to life (and medicine/dentistry/pharmacy) than just sitting in the bio lab. In fact, med schools highly encourage (and sometimes even require) applicants to take coursework outside of the sciences. Psychology, art, literature, philosophy, and other humanities will expose you to other perspectives on the human condition, and you will actually be a *better* professional because of it.
When medical students get kicked out of school, is the problem that they couldn't hack it academically? Usually not. It's usually because of issues with professionalism. When patients complain about doctors, is their biggest concern that the physician isn't knowledgeable enough? Usually not. It's usually because they don't like the doctor's bedside manner. No matter how smart you are, and no matter how much medical information you know, you won't be a good physician unless you're also good at understanding and interacting with people from all walks of life.
5. Everyone will think you're a joke (see #1)
This is the biggest fallacy in your post of all, and the reason why I felt the need to respond. *No one* will think that an applicant with a non-science major is a joke. In fact, statistically, non-biology majors have *better* odds of being accepted to medical school than do biology majors. You can go to the AAMC website and look up the data if you're interested.
OP, you should major in whatever you want. As long as you complete (and do well in) the four prereq courses I mentioned above, and you do well on the MCAT, no one will care if you major in something besides chemistry or biology. In fact, it may even be an asset to your application, as well as make you more interesting to interview.
Again, I can't emphasize enough to all of you that college is the best opportunity you will have for most of your adult life to take some time to stop and smell the roses. So, take classes in medieval studies if that's your thing. Go study a semester abroad if you can afford it and you want to really learn about culture and language. Fifteen years after graduating college, I don't at all regret not having taken more science classes, because I had more than enough science classes in grad school and med school. I am required to attend five hours per week of medical lectures in residency, and I will be required to continue taking "refresher" classes as an attending physician for the rest of my career. You, too, will have the rest of your career to study your profession. Don't waste the opportunity that you have now to study something else just for the sheer fun of it.