The point is, the general public has NO reference point on which to judge any particular science topic. No, they don't have to be capable of doing that science themselves, or doing the calculations to believe.
If they understand enough science to know how it works then they can have enough of an understanding to evaluate the theory.
I got into a discussion about AGW in a blog and made the statement that I understood the theory and data. One woman, who obviously didn't, got upset, claimed she could understand the data as well as I and became downright angry when I asked her why then were her conclusions counter to what I said, and mainstream science had to say. I'm far from being an expert, but my entire education has been based on science, not the liberal arts. I admire artists and musicians, or even business men with MBAs who chose their fields because they like those fields. With the exception of the MBA which has potential they realize and understand the likelihood of their chosen field supporting them in the style to which they'd like to become accustomed to is close to nil. They love their field and understand the prospects. The key words are love and understand. However there is absolutely nothing in these fields to aid in understanding science.
Many chose the arts because most of the courses are easier and contain very little math. When asked why she didn't choose science because an OWS demonstrater stated, "because those courses are too hard. I graduated at 50 and earned a full ride for my masters in CS as a GA.
Unfortunately a degree does not make a person intelligent, it just shows they have been educated.
For many years you only needed a degree. This ended up in many useless degrees that taught very little useful information. Gone now are the days of "any degree". The degree needs to be in a specific field, or closely associated field. Still. students run up horrendous debt, earning these useless degrees. No jobs? Continue on and earn an advanced degree in the same useless field and double the debt! I think they need to make practical decision making and basic economics mandatory before allowing entry into any college, or university. I taught many students as a GA, I wondered how many of them ever made it into the university.. Their ability to solve practical problems was abysmal. Out of 200, mostly business students, I had maybe 10 who could type. This was intro to CS, something most on here would find very boring. It was hoe to turn 'em on, turn 'em off, load a program, run a word processor, spread sheet, paint program, and combine the results into a paper. IOW an add for a job with some imaginary company. The best one was for a condom company. The guy was a good writer and understood the assignments. He received a "A". There were probably 10 in there who weren't going to make it. A course, most 5th graders could ace and I had 10 college students who were going to fail. I had one Einstein who took a girls disk out of the computer and turned it in as his own work...with out even changing the name on the paper. He sat between my boos and me in a small, hot room. I'll swear we could have put a drip pan under him and got enough grease to make candles, but he never cracked, so all we could do was dock him (and her) a grade, Her for sharing homework, and him for mistakenly turning in the wrong disk.
So, I can well understand why far more than the majority do not understand science.