I was not an OT purist at first. I actually saw the films for the first time when the Special Edition was released in theaters, I was around 7 at the time and I loved it. I remember I had a friend who had the THX VHS and I used to borrow those all the time. I got the Special Edition VHS set that Christmas and for years those used to be the way I watched the films. However even back then there was something I always appreciated about the old releases.
Flash forward to 2004 when the DVD's came out. I was pumped beyond belief. Back then I was still into the prequels (that changed dramatically over the years) and the Special Edition changes were still unobtrusive for me. I got the DVD's and immediately I knew that something was wrong. I was only 14 at the time so I had yet to know about the technical hiccups like the crushed blacks, the color correction, the inconsistency with the lightsaber colors but there was still something off about it. So I just sighed and accepted that these were the versions I was going to watch whether I liked it or not.
2006 rolled around and I heard about the GOUT release. I snagged those Day 1 and I dug it. I didn't understand what people were complaining about the non-anamorphic transfer. I had a 4:3 TV back then so I was unaware of the shortcomings of this release. Two years later, I got an HDTV and popped them in again on my PS3 and I finally realized what was wrong. For me that was the straw that broke the camel's back. That combined with Lucas' comments regarding his disdain for the originals is what made me become an OT purist.
I lurked around the site every now and then over the years but when I found out about fan projects like Harmy's Despecialized Edition or the Star Wars Begins documentary, it finally convinced me to join the forums and I'm glad for that. Now I have my copies of the original versions in high quality that I can show to anyone who's unfamiliar with Star Wars without having to worry about explaining why Anakin's ghost at the end of Jedi looks inexplicably younger.