You don't need to log in with your MS account in VS Code yet. They clearly don't want others to be able to download the VSIX unless you use VS Code, otherwise

You don't need to log in with your MS account in VS Code yet. They clearly don't want others to be able to download the VSIX unless you use VS Code, otherwise they wouldn't have hid the button in the UI. Either they already know, or they'll soon discover, that others can still download the VSIX so that's why I'm saying that we'll soon see VS Code requiring login in order to download extensions. Basically to finish what they just now started.