they should really move to linux on USB stick then, long time ago... (e.g. KopiemTu )
Linux is more targeted and easier (because they can look in sources) to hijack, just you do not know that you were hijacked, because you need specialistic knowdlege to trace hacker in your system and trust me it is not easy task
untrue.
having the sources means that the whole world can fix vulnerabilities.
and guess what? they do.
You forget the whole world likes sitting in multiple different distributions.