As far as I can recall, he's never killed someone out of mere personal dislike.

I wouldn't be so sure about that: Licence to Kill was a vendetta, not working for the government.

Likewise, if I remember correctly, he's had his license to kill removed at other occasion(s?). That didn't stop him killing anyways. Granted, there were also some blurry cases of "you are officially fired but actually you keep working for us *wink*".