Neither of them can.
It's a sad example of the end justifies the means.
Some of them are overcome by the Communist vision of things, and think that to make an omelet it's necessary to break a few eggs. Some of them have probably wiped Teddy's history out of their minds and still think of Camelot. Some of them are country clubbers who volunteer for Planned Parenthood and put the right to abortion and the right to perversion ahead of everything else. Teddy may be a murderer, but he can be relied on to preserve their right to an abortion.
Yes, it's pretty sick, but it's easier to think that way when there's a whole culture thinking the same way.
I actually have friends who are friends of Teddy Kennedy. I remember an incident when I was helping my wife who had volunteered to do the spaghetti dinner for the kids in the club kitchen, and I told a joke that was going around at the time. The Queen Elizabeth II had hit an uncharted reef somewhere off the coast, and the joke was that it must have run into Teddy Kennedy's car.
Just after telling it, I looked up, and there was Teddy's friend and host (the good Senator was there for the weekend), who had just walked in, scowling at my back. A bit embarrassing, but I couldn't feel too sorry about it, because if anybody deserved it, it was Teddy Kennedy.