I'll say this once more, you are not anonymous on social media, whether you upload id or not. You are traceable via your broadcast IP adress back to your provider and they can identify the household from your router IP.
You can be anonymous, but most wouldn't know how to do that.
The police do not have the resources to chase racist abuse on social media so it is ignored.
If you want to tackle anti-social behaviour vote for a government that won't strip the legislature to the bone and have a leader that isn't racist and has an apetite to stamp it out.
ID's for social media would be useless without a legal system to back it up. That legal system is the responsability of us all in who we vote for and whether we want to spend additional taxes in creating a better society.