It literally was my initial warning
Correct, but you have also said that it links your transactions no matter what, and that transaction links are created by Whirlpool coinjoins, both of which are incorrect.
It links your transactions no matter which coin you consolidate it with
I continue to quote the post where I traced the Whirlpool transaction you provided because people need to be aware of the transaction links created by Whirlpool coinjoins that can be avoided by using WabiSabi coinjoins.
Now please can we stick to the point and not to semantics?
A man sends his coins to exchange E and receives different coins C after a while. In your opinion, this is a bad practice
Yes, because an exchange isn't designed to offer on-chain privacy.
On the other hand, if a man sends his coins to a dedicated mixer M, and M sends those coins to the same exchange E, getting the same coins C back and then sending them back to the man, you consider it good practice.
MixTum says they're mixing your coins with investors' coins. I'm not sure about the exact procedure they follow, I don't believe they're just randomly selecting an exchange and sending your coins there, under their full name. You can ask them that question in the appropriate thread. I am not obligated to provide an answer, nor am I able to.