[ve55]

Just because every transaction is public does not mean that it's impossible to mix bitcoins, as transactions can have multiple inputs and outputs. It's difficult to mix, but keep in mind perfect information isn't available to those doing analysis, and companies like chainalysis also use a lot of off-chain information to help them draw conclusions.

[sgp_]

It's not impossible to use properly, but it requires time and money. Just to enter the Samourai mixing pools, for example, costs ~$5-270, exclusive of Bitcoin miner fees. Mixing can also take days. Mixing may provide the intended effect for some people, but it's certainly not something for non-enthusiasts. Plus, Chainalysis and other companies will just mark the whole mixing pool as higher risk anyway and flag those deposits with exchanges, even if they can't trace it.