User blog comment:David117/yukino and.../@comment-7418318-20141005084831/@comment-7418318-20141005145641

Yes, Rogue was the only (or first) one to question what Jiemma did, but then he was also the only member of Sabertooth who not just didn't laugh at Lucy's torture, but looked away in shame and then didn't jump in front of Minerva to defend her in the aftermath, so I'm more inclined to contribute it to him just being a better person than the rest of Sabertooth, rather than any romance.

Or maybe having Frosch had a positive influence on Rogue's personality. ^^