Even the WWW was actually popularized first in the US, specifically NCSA made the first web browser with inline image support which is the origin story for every modern browser (and is part of why every browser’s “User-Agent” identifies itself as some variety of “Mozilla”… the “Mo-” comes originally from Mosaic).

Of course they were not the only people ever involved at any step or of any specific technology, exclusively, but the US played a huge and honestly significantly outsized part in the initial development of the internet as we know it, and that continued for decades (and arguably still does). That’s why they can and do claim responsibility. Because in very large part, they are responsible. It’s not unfair to acknowledge facts. Someone had to lead the way. That was the US. Others followed, and helped, and sometimes led a little bit of the way in a particular area. But mostly, the US led the way to the modern Internet, leveraging both significant government funding and the tech-utopians of academia, then-established-but-now-forgotten tech industry veterans like Xerox and DEC, and the capitalist innovators of Silicon Valley to attract and support the best people and ideas they could use to win almost every tech race they participated in, which was almost all of them.