Given how wide the classification of science fiction is I suppose the answer would be yes, I would expect the fiction of LeGuin for example would make you nicer.

But also considering how wide the classification maybe there is only one particular subset of Science Fiction you like?

I prefer Space Opera (e.g. Dan Simmons), but I have read pretty much every other catergory of science fiction, too (dystopian, hard, soft, parallel worlds). I have a bit of trouble wit Steampunk. But anyway, even this is always better than (e.g.) thriller fiction. Always try reading thrillers once in a while and always regret that I started reading.

I'm sure it would. If nothing else, the underlying premise of most SF/F is "What if...?" and presumably the practice of thinking about consequences makes you nicer, or at least slightly more compassionate.