Many people take risk while trying to enter the US from South American countries. They face harsh conditions, including long walks in dry and very hot condition. Many women are raped en route by degenerate amigos or cartels. This on top of the fact that these Nepalese spend tons of money for the "opportunity" to just enter the US, forget about the papers.
So if a Nepali, who is a PR or a citizen, wants to offer a good opportunity to be legal by marrying then people shouldn't be complaining like that. Many people wants to help others while benefiting in return as well. Quid-pro-quo.