Science, in this day and age of the internet and "experts" on everything, is sometimes not all that accurate. People can take scientific data and use it in different ways and in bad ways. Sometimes the data itself is bad, sometimes its the way an argument is being presented, or the analysis of the evidence and data is flawed.
Students need to be able to look at science information and resources, think critically about them, be skeptical of it, and understand if it is good or bad science.
Andy Brunning of Chemistry site Compound Interest has put together this guide on warning signs for bad science.