First of all, there's actually a very easy way to get rid of "Thy Flesh Consumed." Download a Shareware DOS edition of the original Doom. After installing it, search its directory for the file called "Doom1.wad" and delete it, and replace it with the "Doom.wad" file from Ultimate Doom. Now run the game. It's now the full game... except Episode Four isn't even an option! Congratulations, you now have the original Doom, just the way you want it (except that the title screen is different, but please tell me that's not going to be a point of contention). And the best part is, you didn't even have to do anything illegal!
In fact, all DOOM level/episode information is contained in the WAD, so if you really don't like Thy Flesh Consumed, all you have to do is find an older WAD file from before "Ultimate" Doom.
And there's an even easier way: Simply don't play "Thy Flesh Consumed." The original "Knee-Deep in the Dead", "The Shores of Hell," and "Inferno" episodes are all there, completely UNCHANGED. For all intents and purposes, all "Thy Flesh Consumed" does is make itself an option when you start a new game (and change the title screen, but if you're running a Windows or source port version you won't even see this).
Doom's situation is NOTHING LIKE Star Wars. You can't watch A New Hope and simply "ignore" Greedo shooting first, or all the banthas that roar into the camera. You can't watch Return of the Jedi and just "ignore" the new ending or the musical number. You CAN play Doom and simply refuse to play episode four, so really, complaining about it is picky.
Again, I hope this topic is some sort of joke.