If you are not a citizen, you cannot vote. Nor can a citizen vote twice. I'm blown away at how many people still believe this bullshit.
The problem is that although what you posted is absolutely true, it does not fit with some folk’s agenda, so they ignore the facts or convolute them to suit the message they want to send. It is not just the average person who does this, it is also people one would think should know better.
The incidence of fraudulent votes in U.S. elections is minuscule - certainly nowhere near enough to change the outcome of an election. It is a non-issue except to folks who want to believe otherwise.