work on Internet Explorer doesn't mean we will support it on Internet Explorer. Conversely, when we say that we will not support Scratch 3.0 on Internet Explorer, that doesn't mean that it won't work on Internet Explorer.Adding to that, IE only exists today as a means of browsing legacy sites, as newer browsers break some of them. I think just because Scratch 3.0 happens to
Another way of phrasing it might be, if a bug in Scratch 3.0 occurs only in Internet Explorer but not in any other browsers, we wouldn't bother to fix it.
Your school should not be using IE, it should be using either Edge, Firefox, Chrome, or any other mainstream browser.
IE still gets a notable amount of use from organisations such as schools or businesses - as an example, some legacy software uses ActiveX, which requires Internet Explorer and I know places out there that still keep this stuff around