I'd say that works for some people but not all. There are some who fill a more trainer role, can easily mold and shape a submissive or slave without becoming emotionally attached to the point of love. However, for me, the question becomes, if I don't at the very least care about this person, why am I taking my time to mold and shape them? It's not worth it for me to spend all of that time and energy if I don't feel like there's a connection behind it. It doesn't have to start off as love, but I think for many it can end up there, just as it can in any other vanilla relationship. I certainly wouldn't call it a requirement or necessity to love ones Dom/me or sub/slave, but it is definitely possible to do without losing control or the situation. If anything, the love, if shared by the sub/slave as well, could make things easier, because the sub/slave would be more devoted to the Dom/me and looking for even more reasons to please. But, as always, just my 2 cents on the matter.