People with money and influence will always try to impact law. In EU it happens through actual bribes which is far worse. (Pretty much like India). In USA an immigrant like me can join hands with 10K immigrants and find enough support in congress openly by hiring lobbiest to advocate for the cause I care about. That is how democracy should work.
It is easy to see lobbying as bad by taking examples you don't like but in reality it is a great example of how people can convince their representatives to pass right kind of laws, legally and with enough regulation. In most countries this happens to secret middleman and nights in shady hotels.
> a majority of US people is in favor of more limitations to gun rights
It is not clear if that is the case. Of course majority of people is irrelevant because this is not a mob rule. That is why we don't allow crowd in SF determine what people in Montana want. It is all fair game.
Secondly, people like me who care about guns care about it lot more to actually form lobbies. On other hand folks who dislike guns only talk about it but will not lobby or donate for the anti-gun causes.
I recommend this excellent video about why NRA despite with a shoe string budget is so much more influenced than many other lobbying groups.