You're kidding, right? (I can't tell.) There have been plenty worse. The original Bell Biker had those air scoops molded into the rigid shell that formed basically a sharp-edged can opener pointed at your head. If you hit hard enough to compress the styrofoam, which was designed to happen, your scalp would be pressed against this sharp edge as if it were designed for penetrating your skull. Bell recalled them later but didn't do much to get the word out, and I saw people still wearing them long after the recall.
Then there were the leather helmets — surely you agree a Skid-Lid is better than that?! When I first started riding, helmets were required for amateurs, optional in the pros so almost no pros wore them other than for certain events. The "leather hairnet" is what everyone wore, because there wasn't really anything else. And yes, they were considered helmets, and satisfied the helmet requirement for amateurs.
Or the ones that were never intended to pass any kind of testing, like a Brancale. For people who wanted the "helmet look" I guess, but without any actual protection to speak of. Look at this guy's forehead and imagine how much padding there could be in there. Less than with a leather hairnet.
When Tom Broznowski won the US National Championship Road Race (amateur) in '81, he was sponsored by Pro-Tec. It was the first major US race that I can recall where the winner wore a helmet with a shell, what we think of as a "real helmet" nowadays. Those Pro-Tecs were worse than a Skid-Lid in my opinion, but at least the shell was closed on top, which seems to be what bugs people most about the Skid-Lid. Remember though, the Skid-Lid's main competition back then was from leather hairnets, which left as much or more of your head "uncovered".
When the Pro-Tec came out, I kept using my Skid-Lid, mostly for ventilation reasons. I think they're pretty similar in protection, since they both use squishy foam rubber instead of more rigid styrofoam-type stuff that all modern helmets use. That rigid stuff collapses permanently in a crash, absorbing energy as it does. Squishy foam just stores energy temporarily, then returns it to your skull as it rebounds. Which is still better than nothing, but only the crushable kind can pass today's helmet standards, I think (I'm no expert).
Maybe I just don't want to admit I was an idiot for ever wearing a Skid-Lid? I even had a Bell Biker before that, starting in about '75 I think, and I raced in a Brancale (before the Skid-Lid I think). Proving that I'm a sucker for bad helmet designs. The Bell, Brancale and Skid-Lid are all still around here somewhere... man do I have a hoarding problem. I still have an original Giro too, the one with a lycra cover and no shell at all, just the styrofoam. You could get the lycra covers in all sorts of garish '80s neon colors and roller-disco patterns. Giving all cyclists a bad name, to anyone with a shred of good taste.
Mark B