That's DMB's opinion, which none is obligate to agree with. Was Windu hindered? By what?
I agree, that Windu was hindered in his duel against Depa. But against Sora? He was grieved by Sora's betrayal, but he was also determined to deal with him. He was even the first, to ignited his saber. They started fighting, Bulq was even able to Force push him. By reading the panles, we can be sure, that fight was fierce and intensive. And at the end, Windu was able to beat Bulq mostly due to his superior Raw power in the Force.
There is nothing anway, that would suggest, that Windu had any kind of advantage in a duel (unlike Dooku, who was able to disarm Bulq from his shoto, for example).
Things gone this way, perhaps due to Vaapad's mechanics. Sora should be clearly inferior at the beggining, as Windu was clearly better duelist. But that wasn't happened, perhaps because Bulq and Mace knew each other quite well (which is a very specific scenario). That gave Bulq a necessary time, to sank into Vaapad and amp himself on Windu's dark emotions. Which could make him equal to his superior, like in Windu - Sidious' case.