I don't feel very convinced by the case you are trying to make here.

You did not mention colorette until you were forced to do it. Why not talk to the author before making a fork?

You mention that you disagreed with changes in colorette, but you have no evidence for it. If you discussed it in an issue or PR, that would be easy to find and share.

You took all of colorette. The "backported" performance improvement is a single line of code. That you try to make it seem like exactly the same thing seems childish and bullish to me.

If you are really not acting in bad faith, why not drop your fork now that colorette has changed the API back?