For Karder it's all about dominance, not love. So, he may dominate some men by fucking them. And again: you can turn off gay content completely in the Settings -> Toggle Fetishes settings.
Well, anybody can have it's own opinion about what is "manly". Man or manly is not synonim with heterosexual. Personal behavior or sexual orientation are different things. There are heteros less manly and gay very manly.