Step 1: make a bunch of addresses Step 2: the world know it was you
That reduces the anonymity set for everyone else. They thought they were mixing with you anonymously but now that you are revealed, your participation in the mixing is useless, people would have done better to select someone else.
Combine this with Sybil attacks, criminal investigation, and other unmasking techniques and you might get the anonymity set down to 1 for a particular output, allowing you to further reduce other anonymity sets.
I was not aware, but apparently the Monero blockchain has a snowball effect to help mitigate this.