Perhaps to you, but I think that attitude is rare. I think most people find a place where they'd like to eat, and then they choose the easiest way to make a reservation -- the difference in convenience between Opentable and the telephone is pretty small. If I'm going to spend $$ on a nice meal, finding a good place is my priority; if I need to call them or tolerate their shitty Flash website, so be it.

Personally, I rarely use Opentable: apart from the fact that they take some of the restaurant's revenue, they can also report false negatives. For at least one restaurant I go to often (Ad Hoc in Yountville), there is almost never a good time available on Opentable, but there often is if you call the restaurant. Since I can't trust a "no availabilities" result from Opentable, it is easier to just call and speak to a live person.