I think it's the timescale that bothers me, in part; I don't have the same objection to, say, cervical smears which tell me whether I might be at risk for cancer in the coming few years. That allows me to do something about it in terms of possibly readjusting my life plans. But I can't plan on the basis of some terrible thing that might happen in 20 years' time; I'd just have to live with the knowledge that this was likely to happen to me, which I don't think would be good psychologically.
It's true that almost everybody expects to be mortal (the exceptions are a few religious people and a few quasi-religious geeks who think the Singularity is going to cure death). So you always have to run your life on the basis that you have a few decades at best and possibly even less. But I'd still rather not know the probable time and manner of my demise more than a few years in advance, I think.
In non-morbid news: Stockholm is full of magicians and flamboyantly gay people with rainbow banners at the moment. I find this very cool, it's a bit like living in the Paul Gallico novel The man who was magic.