I think the second part of your question might be based on a false premise. There has never been an organized clerical united front against science.

Most of the accusations leveled against the Catholic Church stem from either a misunderstanding of the Galileo affair or what happened with Giordano Bruno.

With regard to Bruno, he was not executed for proposing any revolutionary scientific ideas (which could not be proven at the time). The official reason for his execution was heresy and he definitely did advocate theological positions that would be considered heretical by any standard. Even though his execution did occur in the Papal State, a heresy execution in this time period would be more concerned with the political implications of the heresy. Heresies had traditionally been connected to political. Since Protestantism brought France into a civil war that ended two years before Bruno's execution, this would have been the situation that ecclesiastical authorities were most concerned with. Although they would have objected to his theological views as well, the primary consideration would have been to stop him from getting involved in something like that. I would go so far as to accuse the people who attempt to portray him as a martyr for science of intellectual dishonesty.

The Galileo affair is another situation in which the Catholic Church is wrongfully accused of being anti-science. In actuality, Galileo Galilei was and remained an observant Catholic. However, he had a tendency to insult people who didn't treat him as if he was the smartest man in the world by default. When you call that many people stupid, especially if you publish a book that has a character named "Simpleton," who expresses what you portray to be the pope's view on something, you will end up making very powerful enemies who will be looking for opportunities to retaliate. That opportunity presented itself because France found itself on the opposite side of the Thirty Years' War from Florence. France demanded that the Catholic Church punish Florence, backed by threats to leave the Catholic Church similarly to how the Anglicans left over the previous century if that did not happen. Galileo found himself in the unfortunate situation of being prominent enough to be noticed, low enough that the ruling family would not object too much, and having driven away everybody who might want to speak in his defense.

The Catholic Church has a long tradition of clergy-scientists. A few who come to mind immediately are Nicolaus Copernicus (first prominent heliocentrist astronomer), Nicolas Steno (father of paleontology), Gregor Mendel (father of genetics), Georges Lemaître (originator of Big Bang theory), and Guy Consolmagno (current director of the Vatican Observatory).

An interesting book that I recommend (directed at a popular audience) is Would You Baptize an Extraterrestrial? by Brother Guy Consolmagno and Father Paul Mueller, S.J., which is about the Catholic Church's relationship with science. It touches on things like Galileo and Bruno, as well as explaining the reasons why the Catholic Church has been a longtime major supporter of science (as Jesuit scientists, the two authors seem to particularly like the "We want to understand God by learning more about His creation" explanation).

However, some anti-intellectual strains have taken root in Protestantism. The reason for this is the concept of sola scriptura, Martin Luther's idea that all valid religious knowledge must stem from the Bible. The Catholic and Orthodox Churches have always rejected this because they regard Church tradition to be of parallel authority (indeed, there is no denying that the Bible canon was compiled through Church tradition even among those who hold to sola scriptura). This necessarily led to a disregard for what was, at the time, around 1500 years of writings that debate what interpretations of the Bible were compatible with Christian teachings. As a result, literalist interpretations occurred based on the idea that since the Bible is the sole source of religious knowledge, its meaning must be self-evident on its face to any reader. Consolmagno describes the resulting trends, such as creationism, to be a form of paganism, reducing God to a nature god, rather than a supernatural deity.