There is one key property of scientific thinking that is often overlooked but crucial to understanding how science works. That property is the null hypothesis. In practice and to simplify a technical point, under the null hypothesis a claim is assumed to be false unless and until it is supported by evidence. In normal human communications, things are assumed to be true unless proven false, but in science, that outlook is too undisciplined to lead to anything useful. It is because of the null hypothesis that scientists are regarded as skeptical of ideas unaccompanied by evidence.
His explanation of why logical fallacies should be avoided:
Students of debate learn to avoid what are called "logical fallacies", tactics that have no place in a productive debate and that can only waste the time of the participants.
[...]
It is important to understand that logical fallacies are not merely
weak debate tactics, they represent arguments that have no validity
whatever and have no place in intelligent debate.
And he also makes a few specific points about creationism/intelligent design:
Religious pseudoscientists, like the advocates of "intelligent design", e.g. creationists,
have the same goal and use the same strategy as psychologists. If
science can be defined as something that doesn't require evidence, then
pseudoscience becomes science by decree.
[...]
Achievement of this goal would require the acceptance of untestable
supernatural agencies and the abandonment within science of evidence,
experiment and testable theories. As before, everything is gone but the
name.
This demand has its roots in the
realization that science can produce vaccines and in other ways
alleviate human suffering to a degree that prayer doesn't seem able to
match, and rather than reconsider their attachment to an untestable
belief system, truly dedicated religious believers would prefer to
dismantle the modern world, starting with science (nothing is so
offensive to a religious believer as an effective non-religious life
strategy).