Surprise, surprise, it all comes back to Harvey/Lidstrom. At some point you might just have to accept that your opinion is the minority one. And it's not because the people who hold the majority opinion have some inherent bias, not because they have completely failed to consider differences in league strength/talent pool, and not because of some nostalgia factor. After weighing all available evidence, the majority conclude Harvey was simply a better hockey player than Lidstrom. Full stop. End of story. I disagree with lots of player rankings too. But you know what? My ranking isn't the "answer key". It's only my opinion. When I think that player X is better than player Y, and 90% of people disagree, I conclude that I simply have a minority opinion on the matter. I don't go around saying those 90% have some fundamental bias or have failed to properly evaluate the situation.
Bolded: Calling Ovechkin and Hull "mirror image players" is evidently where the disagreement lies. In the opinion of most people, Hull was better at every facet of the game besides goal scoring, which is the only category where these players are "mirror images". Like Lidstrom and Harvey, all the available evidence has been weighed, and almost everyone has agreed that as of this moment, Bobby Hull was simply a better hockey player than Ovechkin. You're free to disagree, as is everyone.
If such biases existed, they should be evident across the board. But of course, you can only find small little pockets of the list where older players are more prevalent than newer ones. Rather than accept that random variance in any sort of list-making endeavor is going to lead to certain eras being more represented than others in certain spots, you go screaming of bias, and cite the same old tired examples while completely ignoring the broader picture.
The "half the top 20 are from pre-baby boom Canada comment" is telling, and does not help the position you are trying to represent. In order to be appear on the list, a participant would need to be born between approximately 1870 (making them prime aged for the beginning of Stanley Cup hockey) and 1990 (players under 30 years old have understandably not had enough time to finish their careers and be appreciated in a historical sense, generational superstar McDavid notwithstanding). Baby boom is understood to be 1946 onward, which gives us an expectation that 37% of the sample (120 years) should have been born post-WWII if absolutely no consideration was given to era differences. Yet at no single point, be it top-1 to top 49, where we presently sit, is the percentage of post baby-boom birthdays ever as low as 37%. The top 9 (44%) is the lowest representation of post baby-boom birthdays, and almost every single sample thereafter it is 50% or higher. Both figures well above the 37% threshold. Your claims of bias in favour of pre-baby boom players is not supported by basic math.