The name was so popular in Italy it ended up becoming a “slur” (though personally the only time I’ve ever heard someone called Guido is when that was their name). I wonder if that will ever happen with other languages and their common names, I’m Russian so I immediately think of “Sergey” as one of our ultra common names.

It's not a slur exactly, but in the United States, "Ivan" is a common name used to refer (usually dismissively) to Russians.

I've heard the same thing happen with Mohammed

It is a slur. Italians just don't really care that much though so it loses most of its power.

WOP is another one, but again it's gets laughed off for the most part.

I always find it strange how some slurs get clung to like people don't want them to go away.

Some slurs have large organizations behind them telling people they need to be mad. Others don't, and people end up not caring. My background is split 50/50 and both of them have common slurs associated with them. Nobody in my family cares cares, including me.

It's actually just a name. https://en.wikipedia.org/wiki/Guido

You might want to actually read that wikipedia post.....

"The slang term Guido is used in American culture to refer derogatorily to an urban working-class Italian or Italian-American male who is overly aggressive or macho with a tendency for certain conspicuous behavior.[3] It may also be used as a more general ethnic slur for working-class urban Italian Americans.[4]"

I'm not American and I know plenty of Guidos. It's just a name, and banning people named that is incredibly discriminatory.

I feel the same. Am I supposed to legally change my name so I can continue to sign up for stuff on the internet?

Okay? Strawman much? I'm not arguing that anyone do anything about it. I'm just telling you objectively what it is. The Wikipedia article YOU cited disagrees with you...