My understanding was that it was the glutes that failed to activate properly in deadlifts. If you're not using the hamstrings, that bar is not going to move, full stop.
Low back pain can often be a consequence of inhibited glutes. This is quite common, arising from postural changes due to the amount of sitting we do. The hip flexors become short and tight and to protect them, the nervous system limits activation of muscles that complete hip extension, ie the glutes.
The end result is deadlifts that are completed (locked-out) with a hyperextension of the lumbar spine, rather than complete hip extension. This will cause you back pain, for sure. When you deadlift, try to lock out by squeezing your glutes as hard as possible, like you're trying to crack a nut between your arse cheeks. Don't worry about leaning way back; this is such a common technique flaw that you see all the time, particularly in crossfit workouts with deadlifts in. This engaging of the glutes will finish the lockout whilst maintaining a neutral spine, which will protect you from back pain.
It may also be necessary to do remedial exercises to encourage firing of the glutes. Search on youtube for 'birdogs', 'bridges' and 'clams' - these are all useful drills. Another thing I found useful, is just trying to engage the glutes whilst standing throughout the day. Putting a hand on one to improve proprioception of the contracting muscle is helpful.
The better you can make use of these muscles, the easier you will find locking out deadlifts and, as a convenient side-effect, you'll put a lot less stress on your low back.
This isn't to say that strengthening the hamstrings isn't useful, because of course it is. But this is a common faulty movement pattern that can be easily sorted, but is often seen in back pain with deadlifting.