You know I don't have/can't produce that data, then OK you'll probably tell me, "I told you all of those centralized mixers/tumblers don't mix/tumble outputs". But I'll also ask you, "OK, do you have verifiable data so we can validate that claim and make everyone shut up"? You'll think, then you'll tell me that the burden of proof is on me because I ask for the data?

Here's the research paper proving the coinjoin protocol turns your coins completely anonymous: https://eprint.iacr.org/2021/206.pdf

Here's the open source code implementing that protocol that you can verify yourself: https://github.com/WalletWasabi/WalletWasabi