I started at 74 or so kg (182 cm, 26). Was post 5 months of chemo though. I started with 2L of milk + 6 scoops of protein a day. In 3 months was about 80 kg. Ended up on 4L of milk + 6 scoops of protein per day for another 3 months, ended up at 90 kg.
Then got drunk for 2 months, dropped to 81 kg. In the year since then I'm back up to 90 kg with a lot less fat and a lot more strong. So it's appropriate in the right circumstances.
Plenty of milk is appropriate for skinny beginners, but not somebody who's been training for a year or more. If you notice you can't keep up with the program (starting strength is very aggressive with load increases), then add more milk.
Eventually you'll reach the point of diminishing returns though, where you just need to slow down.
Read the article "A Clarification" by Rip on the Starting Strength website.