Better to bring people up on truth yes, but, trust me, you start unraveling the "fiction" that people are brought up on and you will unravel a lot more than religion. A great deal of human society is founded and dependent on fiction. Some people just exploit it better than others. Yes religion has been a good tool, but take it away and it will be replaced by another. People who use those basic methods will use any means that they can get their hands on; religion is just dangerous because people will lower their guard easier than in other cases.
You do have a choice about religion, though, in most cases, even if you were born in a religion. Whether or not you really believe is something you should stop and look in to; it would be very sad to take consequences for something you couldn't get behind. There is no opting out in life, there is only taking hits because of conscious decisions and taking hits because you didn't want to take on making the conscious decision. While it can be a very difficult thing if you start to come in conflict with the religious values you were raised with, you have to evaluate which is more important to you... your autonomy, your family, your personal beliefs, ect. Just like with everything else in life, turning your head doesn't solve the problem. Now if we talk about those where they might die if they leave, that is a completely different can of worms from the rest and an even stickier problem for a variety of reasons.
In the case medical stuff, refusing certain treatments but not all treatments is one thing, but refusing all is a completely different beast again. I personally don't support rejecting all medical treatment, but I would have to respect the wishes of someone that did. Remember, they have a right to make a decision and to stand up for that belief. The only alternative if they choose to support a belief like that is to force them against their will which is another slippery slope.
In general, advancing knowledge is always good if it can help people because you don't always have every option available to you. However, while you might not think that it is worthwhile to spend money on that particular medical path does your opinion outweigh the rights of a person who refuses blood transfusions? Should they be denied healthcare because you don't approve? What would you say if it were you in that position and someone wanted to cut funding for research into a medical procedure that you supported but they didn't? Quite truthfully, I believe that is the very issue at the heart of abortion rights and stem cell research except in that case the shoe is on the other foot.
However, a religion making an official statement does not inherently negate a person's free will if they share the same view. For instance, you can say that religions with dietary restrictions limit the rights of the people that adhere to them yet you can also say that people in those religions adhere to those restrictions because they have no desire to eat those things whether or not the religion makes a stand on it or not. The religion could change its mind and drop the restriction, many people would not in turn ignore the old restriction. I remember watching videos in my gender class that talked about the completely covering veils that some muslim women wear, and in it they were very upset about other people coming and trying to tell them what their identity was and how they should express it. They were very passionate about making their own choice about it and it wasn't just a matter of religion.
As regards politicians, in the US there is separation of church and state so you can pursue legal measures to regulate people like you are afraid of, but for others... *shrugs* Rather than worrying about scary religious people, I would say worry about people who exhibit bad judgement. There is a world of scary people with a variety of personal issue out there and you just have to live it to a certain extent. Most of the people that you would have disagreements with will completely fly under your radar unless very specific issues come up.
However, at this point I need to head to bed. I am making stupid typos now, I'm sure my ability to think will soon follow. :/ Nighty Rig o/
