Not true.
First, my wanting people to learn about a subject before they attempt to make declarations about it -- especially a subject as complex as a field of science -- is not about whether I'll "give them any credit", it's about the fact that people who haven't learned about a subject are far more likely to make false declarations about the subject (born of ignorance) than they are to add something to the discussion of actual value. And it's even worse when they're wildly overconfident of their abilities to debate the subject, as anti-evolutionists usually are -- they think that because they've read some creationist attacks on evolution, that they're competent to debate the subject against people who *are* very familiar with the subject. You know how it is when an empty-headed liberal drops by to "debate" conservatism and tell us how it's all "wrong" by simply parroting stuff they've heard Michael Moore say but they've never tried to double-check any of it and they've never read Locke or Adam Smith or the Constitution or anything else? That's rather what it's like when anti-evolutionists try to "debunk" evolutionary biology based on just reading a few creationist sources but little or no biology. It's a waste of *everyone's* time.
When people actually ask *honest* questions (as opposed to for example questions that try to play "gotcha" or rhetorical questions intended to ridicule because the writer feels there is no valid answer), I'm glad to answer them. When people really *want* to learn, I'm very glad to help. But that's rare among anti-evolutionists -- the few times they really ask a question desiring an answer, it's because they think they can use the answer to justify their rejection of biology, not because they actually want to learn with an open mind, to see where the knowledge leads.
That hardly promotes the interests of science. That's why so many people get turned off to science - attitudes of those who use their knowledge to embarrass and insult people rather than trying to actually become interested in learning on their own. Attitude means a lot.
It does, but I've actually seen very few examples of anyone truly desiring to "use their knowledge to embarrass and insult people" rather than sharing their knowledge. (The one Freeper I can think of who does that actually uses it to attack the *evolutionists*, by the way, even though he thinks "ID" is twaddle -- he's got issues.) For the most part, the folks who get heavily into science *love* knowledge and learning and understanding, and are eager to share it with others, not use it as a weapon.
If you think you've seen me stoop to that without provocation, please point it out to me and I'll be glad to apologize.
What we *do* often do, however, which I suppose could be mistaken for what you describe (but which is not the same thing) is smacking people who are being insulting in their attacks on science but who know far less than they think they do. In those cases, it's appropriate to show them just how wrong their claims are and how little they really know compared to the people they're attempting to belittle and insult as being "idiotic" for believing something as "stupid" as evolutionary biology...
Again, consider the liberal nitwits who drop in here from time to time, laughing at us and spewing Michael Moore nonsense as if it were gospel in order to "put the stupid deluded conservatives in their place" -- in response to that sort of belligerent arrogance, the most appropriate response is to demonstrate to them, as thoroughly as possible, just how out of their league they are and how little they actually understand about the subject, in the hopes that it will a) get them to stop spewing nonstop nonsense the next time, and b) get them to realize the extent of their ignorance and prompt them to start learning something for a change instead of swallowing all the propaganda without engaging their critical thinking abilities.