As you can see, they used the word "could," which means there’s no confirmed result yet on where the money will actually go. It’s like they’re implying that in any illegal activity, including this hack, the hackers will automatically launder the funds through a mixer to cash out, making it harder to track.
regardless of what we think of mixers it is true anyway that they could be used to lose traces of stolen funds there could still be other ways of emptying out the wallets or moving tokens from an exchange to another but the most obvious way is of course through mixers
they are not saying it is true but since others have done it in the past this is the most likely method for these hackers to use