IF some do, they'd probably do that as a sense of accomplishment in being able to get with someone from another culture, and it'd make em feel better about themselves, so they don't wanna lose that feeling.
LOL What makes you think this is something limited to one race of men? It's not a racial issue. It's a *personality* issue. Men of any race, age, religion, etc... can be shitty and think of women as property.