They literally said that new characters don't sell and fans reject them (as they should).

One of the He-Man executives blatantly outright said they hijack existing characters and franchises because they have an established fanbase, and they use that fanbase to spread their propaganda. Remember, you can't indoctrinate people with a degenerate agenda if you don't have people to indoctrinate, which is why they anchor their propaganda to existing franchises and established characters.

Ah, found the article: https://boundingintocomics.com/2021/07/05/netflix-director-claims-king-grayskull-and-andra-race-swapped-in-masters-of-the-universe-revelations-because-new-characters-could-be-easily-rejected/

Here is what Ted Biaselli had to say about them race-swapping King Greyskull...

a big hurdle when you’re introducing a new character to a line of so many well established characters is that they are bound to be outsiders, and harder to accept as canon, at least for a while. Nobody gives a s–t about Sir Lazer Lot.

We asked ourselves early on about the need for giant white, blonde dudes in the pantheon of [Masters of the Universe]. And honestly, it makes both characters less special in their iconography.”

I wish I could take credit for being the one with the idea to make [King] Grayskull black. Because now, in the history of all the champions of Grayskull, a black man has a role of prominence. As opposed to just being the guy with the clamp [a reference to Clamp Champ, the only black character to receive an action figure in the original toy line].