Many Central American countries, including El Salvador, do not have the rule of law that we have in the US. They're overrun by gangs [1]. It is a legitimate claim to asylum. "a random person in the US" does not have this same claim, so, no, they do not have enough grounds.
The United States of America has historically been a bastion of freedom. It's no BS -- we need to live up to the inscription on the Statue of Liberty: "Give me your tired, your poor, Your huddled masses yearning to breathe free, The wretched refuse of your teeming shore."
My ancestors (now me and my descendants), likely your ancestors, benefited from legal immigration and didn't even have an asylum claim. The 19th and 20th centuries also saw the demonization of various European immigrant groups. Don't buy the hype, your fortune/misfortune is not impacted by immigration. Globalization has had a WAY bigger impact and was/is inevitable.
[1] https://en.wikipedia.org/wiki/Crime_in_El_Salvador#Gang_invo...