The speaker assterts that people who are the most deeply committed to an idea or policy are also the most critical of it. I fundamentally agree. In my point of view, I concede that people who disagree with an idea or policy may be critical of it sometimes, however, under most circumstances, people who are most critical of it are the ones who are most deeply committed to it.
  Adimittedly, under some circumstances, people who disagree an idea or policy may be also ciritical of it. Their disagreement may just come from their critics to it. Because the idea or policy is harmful to them or conflicts with their thoughts. For example, when Copernicus established his theory that the center of the universe was the sun not the earth, almost all western people criticized him. The theory conflicted with people's belief in God and the thoughts that the center of the universe was the earth. The critics had lasted a long time until people were unfettered from the constraints of wrong thoughts.
  However, I'd like to say when people aren't critical of an idea or policy, they don't care it at the same time. Their uncritics result from their indifference to the idea or policy. In Beijing, China, the government has to limit the numeber of cars which belong to an citizen. Because the more and more private cars have led to many transportional problems. The policy faces different opinions in Beijing and other big cities. But  people living in small villages and towns don't have any opinions about it and even many of them don't know the policy. So people criticize an idea and policy when they are involved in it.
  Finally, people who are the most deeply committed to an idea or policy may be the most critical of it. They just hope the idea or policy can be improved and become increasingly perfect. For example, the Set Theory is one of the fundaments of modern math now. But it was imperfect, when it was proposed at the beginning of 20th century. The imcomplete Set Theory even caused a challenge to the fundament of math in 1910s. On the other hand, to make it more complete and perfect, many mathicians devoted their whole life to improve it. During more than a century, the Set Theory has been approaching to a perfect theory. 
  To sum up, I concede that people who opposite an idea or policy may be critiacl of it sometimes. However, as I mentioned above, under most circumstances, people who are most critical of an idea and policy are the most deeply committed to it. So I fundamentally agree with the speaker.