Eh, this is a bit of a straw man, no? It's one thing to be liked by everyone. It's another for a (presumably) long time, close friend to say they can no longer respect you due to your decisions.

In this case, it's someone who is already making a lot of money, who could make even more by working for a company that builds AI killing machines. Telling that person they are making a serious mistake is doing them a favor. Wouldn't you want your friends to do the same for you?