By this line of thinking, anyone who buys used minis off ebay should be looked down upon. I can spend $40+ on a box of 10 Space Marines NoS, or I can buy a squad already assembled on Ebay for $10.What difference does it make if someone got a better deal then me, even if it's a box that fell off a truck? Good for them. Not everyone can afford to buy new or even to have a full army of GW mini's
As for Using proxies, I have no problem with people using them. Technically most every conversion is a proxy. Converting a Land Raider to be an Ork Battlewagon is technically a Proxy, since the model being used is not a GW produced Battlewagon, yet we alow this all the time. I've seen dozens of award winning conversions that are using all or part of one model to represent another. I have about 5 Rune Priests in my Space Wolves army, only one is the actual Wolf Priest model, the rest are conversions. So it could be argued that I am proxing a Grey Hunter/Blood Claw/Wolf Guard for a Rune Priest.