"I believe the OGL was a mistake in that it allowed for a copy of the game to become a competitor..."
From the perspective of Hasbro I suspect many within the company do feel the OGL was a mistake. If they didn't feel it was a mistake, they would have continued releasing content under the OGL license.
But that it was a corporate mistake to create a virtually unlimited license to use their gaming system, does not make it immoral for someone to use the license as it was intended. Let's not forget, Pathfinder was far from the first full and complete game created using the D20 system and the OGL, and while some of those like Mutants & Masterminds competed indirectly, some of those games were intended to compete directly with D&D. Moreover, even games like M&M arguably kept WotC from publishing their own Supers RPG, and basically all RPGs are competing with each other for attention and play time.
Incidentally, I disagree with the suits at Hasbro that think the OGL was a mistake. Prior to the OGL, D&D wasn't even the #1 game being played. Based on what I saw out there, more people were out there playing WoD colon games and Deadlands than were buying and playing D&D. The OGL resulted in a situation where 3e D&D reached a point where it had basically crushed every competitor, resulting in a "we can't beat them, we might as well join them" situation. If you really don't like D&D, the OGL probably makes you weep, because it crushed all sorts of innovative designs and gaming systems that were being explored while D&D was in torpor.
But again, and this is entirely the point, comments by Ryan Dancey who was the chief architect of the OGL indicate that the Pathfinder situation was to me exactly what was being put on the table here. At the same time Ryan was saying with good reason, "This OGL will give us a competitive advantage in the market, and push even competitors to promote and support our product.", he was thinking, "I love D&D and this will ensure that regardless of what the corporate suits do, regardless of what happens to WotC, regardless of who the rights holder is and regardless what they want to do with D&D, it will always belong to the fans who will if necessary be able to continue printing the game without TSR or WotC or Hasbro or anyone else." I think the OGL was designed not just to help WotC promote their game and make money, but to strongly discourage them from doing the vary sorts of things that they did. If Hasbro/WotC failed to understand that the OGL virtually ensured that if the harder they tried to grasp the game in their hands, the more the game would simply slip through their fingers - that's there own fault. If Hasbo/WotC failed to understand at the time that Paizo's virtual monopoly of IP creation while WotC owned D&D products focused mostly on crunch (and badly balanced often poorly thought out crunch at that) was making Paizo at least for the time being the stronger partner in the relationship, again, that's not Paizo's fault.
The Paizo/WotC divide reminds me of the spat between Pixar and Disney a few years back, when Disney decided it didn't need Pixar and would just make it's own movies, turning what had been a successful partnership into a competitive relationship. Pixar movies were a huge success; Disney's attempts at making Pixar movies flopped. Disney however almost immediately realized just how stupid it had been and made nice.