I've flown approx 20 times in the last 2 years, both domestic and international. I'm wheelchair bound and have multiple metallic implants. I've never been treated with anything but the utmost courtesy. They ask if you can stand or walk through the scanners but they certainly don't force you to.
They have to follow the same rules and methods for checking. Extremists come in all ages, abilities and colors. As soon as you exempt one group (young, disabled, elderly) you create a new risk group. Is the current system safer? I don't know but it's the best we have at this point.
Flying is not a right, it's a privilege that carries it's own set of rules. If you don't like the rules, don't fly. It really is as simple as that. I can not think of any situation where a person is forced to fly commercially, at some point it is a choice.