For example, a person has a wallet or several that are not tied to their real identity. On the other hand he buys Bitcoin on a centralized exchange, verifies his identity but everything he buys there he sends to an address (or addresses) of another new wallet. And he only moves the funds from that address to send them back to the exchange and sell.
It is not necessary to sell on custodial exchanges, it can be easier to make use of custodial exchanges but you can sell on noncustodial exchanges like bisq, hodlhodl and localcryptos which o_e_l_e_o mentioned, you can sell P2P directly which also involves only noncustodial wallet. This is not all the ways to have privacy but it is one of the ways to start and constantly have privacy if other ways are done right.
Don't you know people's information are worth more than billions of dollars if compared to the risks involved and they are giving it freely to centralized organisations. There can be data breach on the centralized organizations, hackers will know the information of people and indirectly attacking them.
Those dex are only for btc right?
About bisq? No, it support few other coins but not many. But this my article is somewhat old.
1.
BsiqBsiq is a good decentralized exchange, currently having marketcap of $681,498 USD (11.75857697 BTC). The reason this exchange is good is because it has good marketcap, it has many trading pairs, it support cryptocurrencies and fiat (BTC, AUD, BRL, CAD, CHF, EUR, GBP, NZD, SEK, THB, USD), this makes it a way people can use fiat to buy bitcoin without KYC needed.
To know about bitcoin trading pair on bsiq, you can use this link:
https://coinmarketcap.com/exchanges/bisq/When I checked it as as at then, I saw it supporting bitcoin, ethereum, litecoin, monero.