It suggests that's unusual or at least unexpected by the audience. It doesn't necessarily mean the person in question thinks they're special for being so progressive, more that they anticipate others would think so.
See, I don't think it's too out of line to say people usually date others who are normal for them. For some people, black people are not normal to them. For most people, transgender and handicapped people are not normal to them (please note I'm NOT conflating the two!). And when someone's not normal to you it brings up fears that it will be harder for you to relate or draw an adequate amount of satisfaction from the other, as opposed to someone more your normal. Which is definitely closed-minded, but it's an understandable hesitation. A lot of people are okay with others existing as long as they don't have to mingle with them, which is shitty, so the person you're quoting is trying to say they're not like that.