This isn't about RU-486.
All these pills are dangerous, because they play with hormone levels and fertility cycles.
When "the pill" first came out, it was widely used by women, often with destructive long-term effects. Since then, it has been played with, weakened, and altered, but it's still risky.
The same with the morning-after pill, RU-486, contraceptive implants, and all the rest of these questionable drugs. If it were not for the overwhelming force of the abortion lobby, and the knee-jerk impulse to look the other way whenever contraception and abortion enter the picture, there would be a lot more questions about all these drugs.