here's an analogy for you, you are an 15 year old kid and you want some beer, obviously you can't get it on your own, you have 2 options, you can either buy the beer with a fake ID or get someone else to buy it for you, if you decide to get someone else to buy it for you then that is what a proxy server does
just take this story, replace the store with this site, the gas station worker as hair loss admin, bruce, or bryan, replace prez with the 15 year old kid and the proxy server would be the guy buying him the beer. the only difference is that people who's ip you use don't necessarily do it voluntarily where as someone buying you beer is doing it on the own accord.