Richard yeah totally, my reasons are not to do with engineering, they are purely the purist notion and also .. it's just a lot more fun (imnsho) to shift gears yourself.
Watch me shifting through 5 gears with the OEM BMW manual gearbox and watch the Mopar in the next lane with a tricked auto. See how my car loses momentum on every gear change, both from the throttle and compressor effects. And note how in the higher gears (with less gear shifts per feet travelled) my car eats him up.
I did not want to give the impression that drag racing an auto is BORING! God no, it's a Hell of a blast every time you go out, and competing at the lights only adds to it. You are also correct in that, the more times you compete, the more that feeling of isolation or lack of involvement in an auto tranny might bother you.
Some also argue that the Group One racecars (other than Pro Stock) are autos. But they aren't! They have to manually select each next gear, usually with the press of an air shifter button. They don't just sit back and wait 6 seconds!
Pro Stock use 5 speed gearbox. Watch the shift light.
Bleeder.