as i mentioned the source code does not contain Remix actions (ofc <form> will not work without js in this case), so the reason why it makes two request on chat delete could be intentional or this is how they designed their api. Also the mentioned issues with actions by author are valid the only nitpick i have are the statements against chatgpt website and the fact that you can avoid actions if you dislike them.
Most probably /backend-api/ that chatgpt's fe is calling is the go or java backend and has nothing with Remix.