Love and hate both require energy (like all emotions), and both are complex. However, at the risk of being really simplistic, I’ll refer you to a pop culture answer (of sorts):
LUKE
… is the dark side stronger?
YODA
No, no, no. Quicker, easier, more seductive.
Yeah, it’s a movie, and a cheesy one at that, but there’s a certain truth in that cinematic exchange. Hate is not necessarily more powerful than love, but as Yoda imparts, it’s “quicker, easier, more seductive.” Unfortunately, the human instinct is to take the path of least resistance, which is why as @ragingloli notes, history is full of examples of long periods (and recurrent episodes) of hate. Hate requires a lot of energy to sustain, and is a lot of work, as @augustlan notes, but it’s also much easier to do.
Love can be harder because it often requires accomplishing things that aren’t as easy, and also consume a certain amount of energy: forgiving others, forgiving oneself, and accepting people, animals, and things for what they are, warts and all.
Love is such a powerful force that it is at the heart of just about all religions, and is the ideal for which we strive. It’s also part of being whole: before we can truly love someone or something else, we must first love ourselves. A lot of people’s struggles and problems stem from the fact that they don’t love themselves, or they feel there is something they must make whole in their life.
Anyway, back to the whole point. For myself, I think that they’re both equally powerful forces, but it is how we approach them in ourselves and in the world around us that determines which is more powerful for us individually. Unfortunately, this battle means that in influential people, the “winner” in this struggle then influences that individual’s actions and choices which then affect us in positive or negative ways. For every Hitler there is a Gandhi.