While it is generally thought that science is a form of cumulative knowledge, this has meant different things. Since Kuhn, new theories are often considered ‘incommensurable’ with old theories. Essentially, a ‘scientific revolution’ occurs in which the old theory is superseded by a new one rather than incorporated into it as a special case.
But old knowledge should not be superseded by new knowledge, otherwise all knowledge is ‘defeasible’ and in danger of being shown completely false at any moment, hence we really don’t know anything. Rather, new knowledge should clarify old knowledge, show its limits and context, but not completely replace it. We should not (and do not) trash old theories that still work. Of course, some theories are shown not to work even in a limited domain and should be rejected (astrology for example).
So science should act respectfully toward theories that have been generally accepted, and try to maintain as much of them as possible. However, this goes against the grain of a scientific culture in which revolutionary change is prized and Whig history is the norm (those who anticipated the new theory are good guys, those who held on to the old theory are bad guys).
This respectful attitude toward the past goes beyond science to modern culture which rejects old ways of doing things and exults in the new, which has become so ingrained that no matter how bad the new is, it is commonly preferred to the old simply because it is new.
We can and should dispute this modern prejudice and arrogance. In particular, we should reject any natural history that deprecates ancient knowledge such as the occurrence of a world-wide flood. This goes beyond what is contained in the Bible but the Bible acts as a kind of referee concerning what is genuine knowledge and what is knowledge falsely so-called.
Before Darwin it was well known that humans are different in kind from other creatures but evolutionists have lost this knowledge in their obsession with showing that everything is different only in degree. So it is precisely this deprecation of the old that holds science back.
There were some ancients (Aristotle in particular) who said the universe always existed (based on a lack of knowledge of a beginning). The Bible affirms that in this respect the myths and legends of many cultures are correct: there was a beginning. But the Bible says more and that is the issue today. For example, the age of the earth is the age of the universe since the earth was there ‘in the beginning’. Starlight was visible on day four, which leads to the question of how starlight got to be so far away (not the reverse of how starlight got to be here).
Respect for genuine knowledge from ancient sources goes against modernity. That makes creationism a threat to moderns and post-moderns. It also goes against the grain of an anti-tradition attitude, which is strong even among creationists. The point is that ‘tradition’ may contain genuine knowledge; it should not be discarded as a whole but sifted through to keep what is good.