Tornado Cash developers aren’t the martyrs you think they are. Just like zkSNACKs, they took precautionary measures to minimize the risk of getting their rights taken away and their lives destroyed by overzealous government persecution. Their website had a built-in compliance tool which would do chain analysis on your transaction. They also blocked US sanctioned countries from their domain.
I know about the compliance tool. But that's not the reason why I said I think it's a shame they are gone and Wasabi is still here in the form they have chosen to be in.
The compliance tool helps those who need to prove the source of funds. No one forces you to use it or share it with any third parties. But you do need to save "the Note". I think that's what Tornado Cash calls it. The note is mandatory to allow you to withdraw the mixed tokens. It's also used if you want to create a compliance report.