First of all, it's offensive to the person who went through the break up. I chose to date this guy, and now all of a sudden he is the scum of the earth, just because things didn't work out. Of course, sometimes that's absolutely true. But there are a million other reasons to break up besides the person is a parasite sucking life from every aspect of your being. Just because it didn't work out doesn't mean that person is no longer valuable or deserving of basic human rights. I saw something worth dating in the first place, and it was my judgment to do so. You telling me that my ex is (insert something horrible) also tells me that my judgment is equally horrible. Maybe it is, but I find that highly unlikely in 100% of relationships.
Secondly, people saying these things were not a part of the relationship. You can never really understand all the complications and nuances that led to the break up. Sometimes it's big and obvious, but even then, telling someone their ex is awful still discounts that person's emotions. I can think of at least one redeeming quality in all of my exes, and some of them I did fall in love with. So if you tell me how evil and disgusting they are, it still hurts me, even if I know that it's not a good idea for me to be with them. If the person who had the break up says that their ex is of the devil, then fine, you could say it also. But take the lead from the actual person who had the break up as to where the feelings and emotions are at, and what's an appropriate reaction.
In the third place, every relationship has a purpose. There is always a reason a person enters into a relationship, even if it's 100% superficial. That ex fit your friend's needs at least for a little while. They made your friend happy, even if just for a short time. Just because they couldn't keep meeting that need or making your friend happy doesn't mean they should be sterilized.
Now, I know I have probably been guilty of this same thing, and I absolutely believe in the idea that if a person isn't willing to put in the work to be with you, they don't deserve you. But that doesn't mean they don't deserve anyone, or life itself. It just means you are not right for each other. That's no one's fault, it's just life. Sure, you could stay together and trudge through it. That is always an option, no matter if your ex actually did something horrendous. But most of the time, one or both of you just realize the effort it would take to make it work is effort you'd rather put into something (or someone) else. And that's called agency - a choice everyone has.
And yep, using agency hurts people sometimes. Welcome to humanity. Learn to overcome it, or your life will be miserable for its entire duration.
I'm not saying this just because I've gone through a break up and am pretty perturbed about what some people have been saying to me, but because I have been pretty perturbed about what people have been saying to me about my break ups since about 2007. People have actually said things to me about my exes needing to be sterilized or castrated. And yep, some of them were pretty awful. But they were all humans and they all had at least one glimmer of good in their hearts. So back off and let people make their choices (even if they are clearly mistakes).
So if you have a friend who has gone through a break up recently, follow their lead about expression of pain, frustration, confusion, etc. I know it's tempting to try to convince them that their ex was the worst person ever to help them feel better, but that really doesn't help anyone feel better. Instead, help them feel good about themselves by uplifting them instead of tearing down someone else.
