Also I have doubts about the onion address he shared, because as far as I know the real address starts with mixorfly or something like that.
Unfortunately, I don't have tor on my mobile so I can't verify it myself.
It's correct however it's the v2 onion link and CM moved to v3 which is the chipmixorfly, see ANN:
https://bitcointalk.org/index.php?topic=1935098.0.
Regardless, I wouldn't dare click any links on the article as it's been established the publisher/author has malicious intent. I suspect the information where the article is based from or copied from is of long ago seeing how a lot of data is outdated. Aside from CM, another closed service is also listed - bitblender.
CryptoMixer has an outdated onion link as well
Malicious article:

ANN
Lastly, it's worth noting that SmartMix.io (on #2) is a scam, see:
https://bitcointalk.org/index.php?topic=5168581.0