I can see how my sumo range of motion would be different...I use it specifically because it is shorter. For Project, I don't see how floor to lock out ROM is any different. He pulls conventional.
We also have to distinguish a definition of deadlifts apparently. We pull from the floor...DEAD...LIFT. We don't unrack anything. We don't start at the top, lower, lift. We pick up, then drop, reset, pick up again, drop, reset...etc. This can't be done on a "platform." We also have to take into consideration the purpose for the movement. We don't do RLDLs, SLDLs, keystones, etc...those are all variations designed to target certain muscle groups. A deadlift, as the weightlifting world knows it, is picking weight up off the floor and locking it out. Whatever you do to alter that to create hypertrophy is a different move, and shouldn't be considered more/less safe than a true deadlift. It's apples to oranges.
I was deadlifting 225 for 15 with a belt back in January when I felt a series of pops and hit the floor...numb from the chest down. Trainer rushed me to ER. Not PL/OL deadlifts, but pick it up off the floor, and hit the eccentric just about mid/calf deadlifts. I thought I was out of commission. Thankfully, learning AR techniques and switching to PL form helped me rehab this injury faster than I expected. Now I am lifting about 100 pounds more than that for reps, raw, with no problem (conventional and sumo).
Again, powerlifters pull 2-3x that kind of weight all the time with no problem. There's a difference in core strength. A powerlifter trains the core specifically to be able to handle this type of stress. BB's don't. For one, it makes your core THICK, and many BB's find this couterproductive to achieving a solid taper.
Poor form + weak back/core = injury. Like Hannibal said, some backs are pretty, some are strong.
Squats are very dangerous to rack, C, and I'm glad you came through it ok. We are getting a monolift soon for this reason. Again, there's a core training difference with PLers, in that a PLer will train partial valsalvas (walkouts) with bar weight as a Max Effort move for time, and also SEVERAL different variations of good mornigns just to prevent this type of injury. We call it chaos recovery. We always goodmorning the weight out of the rack, and goodmorning it back in. Not only does this allow for chaos recovery at lock out/rerack, but at the bottom. If you lose tightness in the erectors and traps at any point in the squat, you're asking for trouble. If you start to fall forward with 1000 pounds on your back, you better have the erectors to regroup and stabalize.
All moves have the potential to be dangerous, so anything we can do to make our own form/variations safer and more effective for our individual goals, the better.