genuine question: why is connecting an old operating system to the internet considered bad for security?
I don't think connecting in itself is usually bad, I can't think of many (on top of my head not even one) vulns in a TCP stack itself that directly allows RCE. Ping of Death is a thing, but not that worrisome. Running weird 3rd party exploitable daemons is not unique for old operating systems.
browser exploits? surely a thing, but highly depends if you are visiting a website containing an exploit kit. And you will miss modern defense features, but that also depends if the websites you visit are actually trying to exploit the lack of those.
old TLS stacks? the most serious vuln ever was a server-side one (Heartbleed), I'd consider most of the client side stuff meh at best. Most servers have disabled old protocol versions already so you'll be mostly missing out on websites because of no cipher overlap.
What else am I missing?
