Nope. Quinlan Vos fell was close to falling to the dark side because of his fear, but he still did have a choice. On the other hand, they didn't 'let Exar fall to the dark side', they forced him down that path. The failure of one's will to resist their own passions is what makes all the dark side so good and credible story-wise, at least to me. The light side is about doing the right things even if there was an easier way, ultimately it was about improving oneself. If you take the 'choice' element from the story, what's left is not the dark side, it's some lame excuse for it. How come using the force to pull the lightsaber to you so you can save your life is dark? If Exar had used some dark side ability, or had been quick to anger, I might be persuaded to buy it, but he always tried to turn to the light first. Nah, the author was probably suffering a serious hangover when he devised Exar's downfall and couldn't think of any better way to justify it.