One of my step dad's friends works with companies installing servers and other various computers and things of such nature (sorry i'm unsure really). Every time he comes over we talk about computers a bit and then we get on to the topic of my computer . More specifically my temps and over clocking. He by no means knows much about enthusiast computers. But when ever i mention my gpu's getting to 80 degrees celsius before i increase fan speeds, he says thats perfectly fine and its well within factory limits. Technically it is because I think I recall seeing them rated for 100 degrees celsius (not totally sure). I guess my question is, if this is true and it's really not a problem why is the entire pc enthusiast community so butthurt about keeping load temps under 70ish degrees?
Well most likely because they are used to working with servers. Servers are designed to run very stable, even with VERY high temperatures. So 80C really isn't something he would care about.
However, 80C is not above or very near the max temperature of many gpu's, it still can damage certain parts of your gpu. Some parts on the gpu can be blown off/damaged because of too high temperatures.
Because GPU's can handle higher temps for longer, than a CPU can. A GPU will happily run 80C+ 24/7, but running a CPU like that will shorten it's lifespan to some extent, worsening the hotter it gets.
Besides, it's always best to keep everything the coolest that you can to make everything last. If you can afford to burn out and buy new stuff every year, them more power to you, but most people can't.
And 72.6C is the max CPU temp for most Sandy Bridge CPU's so that's where that figure comes from (although max core temp is 98C).