They are adding NTR at the end of the game, you can literally just stop supporting them after he is finished with the main story. Asami literally also has a friendship route so not going through her romance story does not immediately spawn a football team to run a train on her.
I can't see any harm this little post could ever do to the current development of the game and the direction it's taking. I genuinely don't understand what there is to be SOupset about.
Also, a "game developed for its supporters" has never existed. You seem to be mistaken about this. A dev makes a game they want to make, people support it or don't, the dev will make the game anyway. Ya'll need to understand that when it comes down to it, whether you think it's fair or not, nobody has "a say" on how a dev makes their game, the only thing you have control over is whether or not you will spend your money on them. I'm not saying I agree with this, but it's just how it works. Whether you can convince RNG to refund you or not is up in the air, but they are not required to do anything LOL