It's only a 5 min read, I recommend it, you might find you have more shared liberal values then you thought, but if you're not going too, let me point out some of the relevant ones here:

Article 12
> No one shall be subjected to arbitrary interference with his privacy, family, home or correspondence, nor to attacks upon his honour and reputation. Everyone has the right to the protection of the law against such interference or attacks.

This is a liberal value. False accusations go against this, so would most of the US politcal tactics employed to smear and discriminate other parties. It's rampant in today's society, in fact you did just that, by trying to compare people who disagree with you as "idiots". You took attack on their reputation.

Article 23
> Everyone who works has the right to just and favourable remuneration ensuring for himself and his family an existence worthy of human dignity, and supplemented, if necessary, by other means of social protection

Wage slavery is a catchy attention seeking way of saying that this right is being breached by a lot of employers.

Article 19
> Everyone has the right to freedom of opinion and expression; this right includes freedom to hold opinions without interference and to seek, receive and impart information and ideas through any media and regardless of frontiers.

This is where it gets tricky. It is your right to be allowed to tell others on social media about any information or ideas you hold. So it seem to make sense that one could tell people that their ex was abusive and a scumbag. And in turn it is fine for others to tell the ex they believe what they think of it.

But what if your ideas are an attack on someone's else honor or reputation? Are you still free to express them? Would it not then breach the other right to not have honor and reputation attacked?

Well yes, this is a dilemma. One where different people lean more on one right or the other. In the US, people lean more on the right to speech, so it tends to be free game to say whatever you want and thus internet mobs are okay.

Now what I think is that there is no real contradiction. You have the right to express yourself freely, but not to hurt someone else's reputation. So expressing lies and falsehoods to attack someone goes against that person's rights, and your right to express yourself freely is for things you believe to be truthful, or things which don't attack someone's reputation only.

That said, and I won't quote them here, other liberal values say everyone is innocent before proven guilty and have the right to a fair trial. So it would be to the person whose reputation they feel attacked to prove that the other person did in fact express lies and falsehoods to attack their reputation, and that person would need a fair trial and be treated innocent until guilty. Similarly no penal offence can be taken against someone just because there is somebody claiming they are abusive and were harassed by them, a fair trial must be held.

That leaves us with how things are exactly right now. Everyone is free to say what they want to anyone else, and everyone is free to any idea they hold of others. And for the government to interfere in any way, there'd need to be a fair trial that proves that one person's speech was a real attack on someone's reputation, and not just sharing their truths.