Banned is the wrong word.

Steam chose not to distribute it because it they understood an early build to include children in sexual situations. Further builds did not dissuade them from the original decision.

Epic, who originally was going to distribute based on the developer filling out some form chose not to after filling it out themselves and finding it had a higher rating (adult only) at the last minute.

The developer speculated it was about a specific scene, but based on both steam and epic there are fundamental concerns about the content that led to no distributing on their platforms, which is not banning, that do not align with the story the developers are presenting. It is not likely to be about one scene that was in an earlier build that was the issue for them.

The important thing is that the game is not BANNED in any way whatsoever. It is available on fewer distribution platforms, which reduces visibility, but is not banning any more than exclusive deals or limited releases are banning on other platforms.

Personally I get the impression that the developers see the content very differently than steam and epic because the developers focus on intent and steam and epic focus on what actually exists in the game.