Is this Windows 8 and 7 comparisons on the same machines? because if it's just grabbing numbers from a bunch of people based on OS than that chart would be inaccurate.
I have no idea whether this is true for Minecraft specifically or not, but overall Windows 8 does have proven performance enhancements, this is a fact.
I don't think being a web design major has anything to do with building computers, not sure why they'd teach you that.
Yes, it's the OS' fault the lamp broke.
Plus, if you get the service packs for Vista, a lot of the issues go away and it's close to Windows 7, same with 8, just update to 8.1
As long as you aren't careless you won't get a virus, I run all my machines with no anti-virus, and windows defender disabled, and don't install any Windows security updates. On top of that I'm not scared to install random stuff off the internet. No viruses, ever.
Sorry if this post comes off sounding bad, I just had to address it.