These muthaf'ers are so thick. So the animals they are modelled on are larely indistinguishable talking male/female
But if you accept that, then you can't shriek about how progressive you are for putting a female counterpart in your game. Either you make them indistinguishable by nature and both characters are androgynous or you want to differentiate the male and female with common biological charcteristics, that make it evident. Differentiating the female with like white-ish/lilac-ish fur is just as bad of a cliche, or implementing anime eyes and jaw.
I don't understand his tweet chain though. Did he leave because he lost the argument, or was a compromise reached? It's pretty obvious that Rivet is a female character because of the standard choices that get made to illustrate artistically that the character is a female (even when non human). Did anyone not know the Cadburys rabbit wasn't a female? There was no T&A there.
In summary, the tweet is just there to self inflate this dude's ego and he is fishing for praise for being woke. When most people just look at it as a work dispute, probably guided by marketing and other stuff that affects the bottom line. The kind of shite we do every day in work but ultimaetly get over ruled by the strategic stuff. It's called being an adult. You want that freedom, start your own studio - that's what the free market is. If all these twitter people are sales then it will be easy.