To humanize is to make something friendlier to humans. Humanizing makes things more civilized, refined, and understandable. You need to humanize characters when you’re writing a story, so people will understand them.
To humanize is to make things more humane and easier for humans to relate to and appreciate. A biography of a murderer could humanize the murderer if it showed he had a terrible life growing up. A factory could be humanized if conditions are made less dangerous. In general, if you’re a human, to humanize something is a good thing. If you’re a robot, get your own word!