Kojima is just sore over his ordeal with Konami. Kojima has a lot of problems and as time has gone by, I totally get why Konami cut him, they've just been more classy and professional keeping their mouth shut and respecting his personal life and not spouting out to the world why he was such a problem for them.
Uncle Ben gave tremendous wisdom to Peter Parker, and as cliche as it always sounds, it's true: "with great power comes great responsibility". Konami gave Kojima too much power and the responsibility was more than Kojima could bear. If you ask Konami, they won't tell you. They'll respond with: "No comment" or "we respect the privacy and dignity of former employees so we don't comment on things like that" or the famous cop out during the PS3 era, though true, but with Kaz Harai and Jack Tretton, but ultimately affective "we don't comment on rumors and speculation" that silenced even the most annoying of press reporters.
In Kojima's case however, if you've been a supervisor before, you get all of this but while we all loved Metal Gear Kojima, once he hit Metal Gear Solid 4 and moved on to Metal Gear Solid V, his head inflated, and Kojima likely has a lot of mental health issues (as is evidenced every time he's released a game, including Metal Gear releases and Death Stranding). In Metal Gear Solid V, you can see how Kojima had way too much control and was trying to position himself, not only above Konami, but above the rest of his team trying to work with him. Metal Gear Solid V: The Phantom Pain (regardless of the episodic format the game had) had Kojima's name, alone, credited a total of 163 TIMES! Just Kojima's name. Kiefer Sutherland's name isn't documented because it wasn't nearly as absurd so it wouldn't be found in common information, but Sutherland was the star of the game, yet Kojima's credited name occurrence burried his. That's telling. That tells you a lot about how Kojima was at Konami, and I don't know Japanese law, I would assume it's similar to American law, but HIPPA in the U.S. prevents an employer from discussing confidential and sensitive information about an employees medical conditions and history. Konami had to have known, but again, after every game release Kojima went into mega anxiety mode and likely exhibited manic behavior associated with depression. It was often discussed during the PS3 era of gaming. Kojima has problems and I, today, can see and understand why Konami cut him. I would've too. He was becoming a liability that after some time, they've bounced back. Media reporter Geoff Keighley isn't one to ask, there's bias there but be was a major contributor to the attempt to sabotage Konami but, Konami remaining professional didn't comment. Just went about business.
Kojima's opinion on this subject doesn't really matter. He just completed a sequel to his former game that also uses similar elements to Metal Gear. Nothing and nobody is totally innovative. Everyone draws inspiration from someone. Some blatantly plagerize. Kojima's work borrows heavily from American cinema and these days, unfortunately, remakes and remasters are prevelent in gaming society, which is unfortunate. But Kojima had no problems or complaints with remasters of his previous games on GAMECUBE, PlayStation 3, PlayStation Vita, and Xbox 360 oh, and Game Boy Color. The most perplexing and the game that negates his whole argument on this subject and proves his ego has been burned and his grudge against Konami through all of this is Metal Gear Solid: Twin Snakes. A remake, but also completely unheard of at that time appearing on a NINTENDO console. Metal Gear Solid 2 appeared on the Xbox when PlayStation was doing everything they could could take care of him and make him a household name. And, just as PlayStation made every effort to help him get back on his feet after Konami cut him lose. Microsoft didn't help him get doing again, Herman Hulst and his crew did providing him with a wooden box that contained a HDD with the Decima Engine on it that cut out all the hard work getting him going faster. No loyalty, just like Konami and PlayStation then, Kojima hasn't changed. Death Stranding was released on Xbox Series S/X. Kojima has no gratitude and no loyalty. It's that simple