Poisoning people and their excuses

I was thinking a lot of excuses. I don't excuse myself but I excuse others. These are the poisoning people in life that poison you without realizing what they do.
Does it make sense? Let me explain it.

Excuses are something bad, aren't they?

Nowadays we use excuse as a bad thing. I am sure that all of you remember 'What's your excuse?' campaign. Excuse means that you don't want to do something because you are lazy, you are not good enough to do it. Like you don't go to gym because of your excuses. You could go to gym, nothing holds you back, but you don't want to, so you find an excuse.
Well, I don't like its new meaning.

Not my excuses

I don't excuse myself as I know that everything is based on my decisions or acts in my life. It is my responsibility to handle the effects of what I did or what I said.

I usually excuse my friends, relatives and collegues. The point is that you can't avoid them as most of the articles would suggest. They are the part of life and we have to study how to live with them without going crazy.

I usually use the following excuses. She can't understand this because she has Asperger syndrome (or autism or has personality disorder, etc.). She doesn't understand it because she doesn't know that her words have an effect on others. She doesn't want to hurt you, she is just ill. Don't take it serious, it was not against you.

But

I think that people should learn or experience that saying something bad has an effect on others. Maybe it doesn't work with every tiny detail because in many cases empathy would be needed. But making jokes about other's death, illness (like cancer) or suicide should have been studied.

As they are smart, they should study this as they memorize many facts from different books. It seems so easy. If I cut my finger with a knife, it will bleed. If I say something insulting, the other person will be hurt. If I talk about other's suicide, maybe this person will commit it. (Well, I know that most of the people won't do it because someone said, but it is possible if the other is actually instable emotionally).

I know that if something seems easy for me, it is not definitely easy for people with social problems. As far as I know there are different improving lessons or courses that can teach the mechanism of human feelings. It is recommended for children, but it could be useful for adults, too.

How to handle

Now I should say that don't take it serious and excuse her, because she is uncaple of realizing her acts. But how could I say it, if I can't do it?! Personally I am struggling with a poisoning person. It is not a new relationship in my life, it started many years ago.
The words still hurt.
I know that I should forget and forgive. And it is my fault that I wasn't able to do it. I know that I should be less touchy and I would help a lot. This is something that I have to work on.

Do you have a strategy to handle these poisoning people in your life?