Take the Apollo moon landings. The alleged conspiracy is based on a number of data points, including:
- There are no stars in the backgrounds of pictures taken on the lunar surface
- There's no dust on the lunar module's footpads
- Shadows are pointing in different directions
- The flag is fluttering in no atmosphere
- Camera cross hairs on lunar surface pictures sometimes appear behind objects
That's not to say that refuting the above claims alone, proves that the moon landings did happen - just that these claims are not proof that the landings were a hoax. Often confused, there is a profound difference, between these two conclusions.
The lesson for us is to not jump to conclusions, verify information, look for alternative explanations, ask disconfirming questions and keep an open, critical mind.