It's really not like that. She was asked by friends where she was registered so they could coordinate gift buying - the standard wedding process. So she setup the go fund me page with a very small goal and told everyone there was no need for donations. And they are paying for the very low cost wedding themselves I'm told.So many people these days expect others to pay for their wedding simply because they cost a lot of money.
If they love each other, seriously .. it's not about money, or the wedding, it's about a special time for them to declare their everlasting love with friends and family.
If they truly loved each other then time has no barrier .. a couple of years, save the money, do the planning enjoy life together.
Your niece however is rush rush rush, no money, wants it all, doesn't care who she hurts. Has nothing to do with the gender in the relationship .. sounds like a pair of selfish little girls that needs to grow up and learn about reality.