I must admit that I never quite understood the perception of Shinnecock as a joyless, punishing slog.
When the fairways are at their standard width, I think the course is eminently playable, certainly fair, and only a small handful of holes (i.e. 7, 10, 11) are really disaster-laden where one can easily make double or worse.
Instead, I think it is that equitable "fairness" and general lack of quirk and whimsy (as well as a standard par of 70) that makes low-handicappers bitch about it being tough and unforgiving. Yes, the greens are smallish and repel weak or overly aggressive efforts, but the areas around most of them permit reasonable recovery (unlike, say Pinehurst 2), and some holes can play quite long depending on wind direction, but I think ultimately the thing that gives Shinnecock the "too tough" rap is simply that the player who averages 75 can easily shoot 85, riding the bogey train all day.
However, for the mid to higher handicap guy, I've seen many a course way more punishing than Shinnecock. The funny thing is that fellow, who may average 85 elsewhere, can easily shoot 85 at Shinny if they have a good chipping and putting day.
Ultimately, I think it's just a course (like a number of great ones) that ratchets up the challenge the more aggressive you get. If you play each hole conservatively, it permits you to shoot a decent score. If you get a bit bolder, you'd better perform to the top of your ability because it will shrug you off like an accountant riding a bucking bronco.