I'm disgusted by those who constantly blame the UN for this or that and don't propose solutions.

Well, several things:
Yes, many intellectuals, many politicians, worldwide, regret that not interfering with internal matters of sovereign states is very damaging to populations when human rights are clearly abused and dictators do whatever they want with their own people.
That is one of the purposes behind the creation of the ICC.
Why can't the US sign it , then?
It's about avoiding dictators' impunity.

Why not be pro-active at the UN, instead of destructive? By invading and occupying Iraq unilaterally, the US has scandered chances to get more pro-active decisions and agreements at the UN about dealing with human rights abuses in countries.

The UN cannot change anything without concertive decisions by its members. It's not the UN's fault, it's its members' fault.

Some UN commisioners come from countries with an age-long disrespect for human rights? Yes, it's true, but those commissioners do not represent their country, but the UN. Those commissioners are not alone, they're surrounded by commisioners from other countries. It's very easy to check on everyone's tasks.

The UN isn't a perfect institution but it's the one with the widest international influence and that's why it matters.

Raoul