google and firefox web browsers both have frequently updated security features and are designed to alert users to sites potentially hosting malware.
IE doesn’t show the warning because, to put it bluntly, it’s an inferior product. So the posters here who were saying that “the site works fine on IE” were still encountering the same malware, but just weren’t using a browser equipped to warn them.
So, Firefox routinely asks Google whether a site is dangerous, or not. This is the default behavior, though it can be turned off.
As I said, I don't trust Google.