"Purist" has changed its meaning over time for me. I saw all of the Special Editions theatrically, and preferred the originals from the very start, so I guess I was a purist right away. But it was no big deal back in 1997--I knew that these Special Editions were just the "director's cuts" (or, more accurately, executive producer's cuts), and I would just always make sure to get the theatrical version when it came out on disc. No big deal. I figured there's no way Lucasfilm would fail to make easy money off its fans, so I just needed to wait...
Well, pretty soon I started with the Laserdisc transfers on DVD, which kept me happy for a while (happier than VHS), but the technical shortcomings were pretty apparent even then. I still believed the OT would come out eventually and this whole "the SE is all there is" was just BS to appease Lucas's ego in the short term while they arranged a proper OT release behind the scenes. A few more years went by and the GOUT was released, which was the first time I actually really understood what they were doing to Star Wars. And then The Blu-rays eliminated all further doubt by dropping the "Special Edition" label. They meant to eliminate Star Wars from history and replace it with the Special Editions, and they were succeeding.
Now I'm a pretty dyed-in-the-wool purist by any standards. And the funny thing is, I wouldn't really even describe myself as a Star Wars fan. I mean, I like the movies and all, but I like a lot of others better.