As a general stat, I think it makes a difference to look at peak dominance vs. and entire career (although we'll see how much difference it makes when looking at these two).
Paul Coffey, for instance, was utterly dominant at his peak. But he only has a 17 point lead over the next defenseman during the span of his career (Bourque), and that's because Bourque was able to play well for longer, not because he was anywhere as good offensively at their peaks. If Bourque had been born 10 years earlier or later, Coffey's lead over 2nd place would have been much bigger. They just happened to enter and exit the league at the exact same time.
So by my count, Shore's best scoring finishes over his competitors look like this:
1929: 26%
1935: 26%
1933: 25%
1931: 24%
1928+1932: tied
Lidstrom's best finishes over his competition:
2000: 17%
2006: 12%
2008: 6%
1998: 3%
Unless I'm missing something, it looks like the stats on the front page were wrong. It seems that Lidstrom led defensemen in scoring 4 times, not 5. While Shore did it 6 times instead of 5 (though two were ties).
But at any rate, I think we still have to give it to Shore over Lidstrom offensively. As I say, the career vs. opponents stat is a bit misleading, as it's more a tribute to Lidstrom's longevity than to the fact that he was significantly better than a guy like Gonchar at their peaks. Single-season dominance is the way to go here, especially when dealing with two players with sensational longevity relative to their era. The closest guy to Lidstrom in terms of games played over his career is Niedermayer, who, despite popular belief, was rarely an elite offensive guy compared to his peers. The only other notable guys who come within 400 games of him are Blake and Pronger, and I wouldn't say either of those guys were consistently great offensively. It's probably telling that the guy in second place over the course of Lidstrom's career is still Brian Leetch, with 500 fewer games played. While Shore's career probably overlapped with fewer notable defensemen, he did play most of it against a legitimately great offensive defender in King Clancy.