#he didn't treat anyone like this during his typical captaincy

[iwouldservehim]

I think the boy called Felix is really significant in Ed's manifestation-of-self-hate Hornigold process. Unlike in real life, Blackbeard is meant to have gone on as a business for decades, and so anything Hornigold did would be a distant memory. That he remembers him threatening to flay HIS skin "and feed it back to him" is one thing, but he remembers the boy Felix, he remembers his name, and what happened to him recounted with righteous disapproval.

Hornigold isn't the vessel of his hated persona by chance, he's the worst he could imagine, and seemingly the one he tried to emulate in his Kraken era as the worst behaviour he could imagine, including a drug abuse to make him not think about his behaviour.

As a captain himself, Ed has clearly stayed away from becoming that before. Yes, he was still revered, but it was inclining towards admiration, most of all for his brains, even while implementing certain stern rules like the pets one, or ordering a British soldier's skin flayed when openly disrespected before his crew, because he will not be seen as taking such audacity lightly.

People act like Izzy was actually doing all the work, but it is Ed he turns to for a "plan" the second time we see them while in peril. If Izzy was there to expedite things as a follower - what a first mate should do - Ed was always the one they turned to to follow, with clearly there being trust there was a reason to.

It's very significant and in line with "I've never seen Blackbeard like this" that Ed trying to personify the Kraken (again, clearly actually inspired by his memories of Hornigold) as "the worst him" was never even him. The real Ed/Blackbeard remembers Felix, some random boy in the crew treated unfairly in a most aghast, judgemental way once he's looking at this "dark persona" from the outside.