[decentralised]

The traceability of very much part of design of most blockchains, starting with Bitcoin. The whitepaper makes this clear in section "10) Privacy" and the article quotes half of the relevant text.

The remaining half states: "As an additional firewall, a new key pair should be used for each transaction to keep them from being linked to a common owner. Some linking is still unavoidable with multi-input transactions, which necessarily reveal that their inputs were owned by the same owner. The risk is that if the owner of a key is revealed, linking could reveal other transactions that belonged to the same owner"

Unlike Bitcoin, account based blockchains make this extra measure of privacy harder as the receiving and sending address is one and the same, however there's no limit to how many accounts one can have, so anonymity is still possible as long as acquiring the coins doesn't reveal your identity.

Those who sign up for cryptocurrency service providers (who are required by law to perform AML/KYC checks - and do so with the consent of their customers) trade away the privacy (of some of their) transactions for the benefits (most commonly, yield and ease of use) said services offer. This is not different from use cases of cash money, where getting cash money from an ATM or most money transmitters will reveal your identity, and while one is free to make in person transactions and remain "anonymous", if one wants to have a bank account or invest legally, then some level of KYC will be in place.

The article indeed asks the wrong question. DeFi can't operate legally without KYC/AML and customers know it. Your comment on the other hand seems to me to be making an error in believing DeFi users don't know this.