Looks like everyone has an opinion on this subject and it is quite easy to make a generalization. They see a young russian girl married to an older man and instantly think, "gold digger". They assume, the only way a young russian lady would chose someone older than her was because he was wealthy. How would they feel if they knew that this woman made twice as much as the man?
Younger men, not all of them, trying to avoid another generalization, but to be frank, young dudes are often quite immature, they don't have the experiences, they dont know how to treat a woman, they are not ready to settle down, life is an adventure and the perfect woman could be right around the corner.
Older men also know what it means to have had their heart broken. They've probably been married or at least engaged and gone through a lot of different relationships. They've learned what it means to be married and they are ready to give their russian brides what they want or need.