My boyfriend got a second rabbit, which he was informed was a female by the shelter, so that his rabbit could have a friend. Turns out the day of the spay turned into a neuter. He attempted to bond his two males, multiple times and they always tried to kill each other. It was a mess. Now, the two males are happily bonded with their own females- totally in love. I have heard tons of stories about bonding two males together, I think it really just depends on their personalities. His two males get along with all of my females, but just not each other. I believe its because one of his males happens to hate all other male rabbits (since he HATES my new male and any male fosters that come though), but who knows for sure. If you want to bond two males I would recommend a few "dates" first to make sure it will work out.
Also, at an adoption event we were talking about how rabbits seem racist. I heard a story about a group of 6 black rabbits and 1 brown and 1 white rabbit being put together. The black rabbits all ganged up on the none black rabbits and were completely fine with each other. Once the other two were taken out the black rabbits then started picking out the "weak links" in their group. I heard another story about rew rabbits forming a little rabbit klan. Very interesting stuff! I wonder if thats always the case. Rabbits are so interesting I feel like I'm always learning something new!