There are a lot of misconceptions about SEO and many have a negative perception about the SEO industry.
For instance, the latest TWiT (This Week in Tech), host Leo Laporte said that he thought SEO was all snake oil. They went on to discuss that SEO is hurting users of search because SEO manipulates search results so legitimate sources are being pushed down.
I would disagree that SEO hurts users. Optimizing your content to include keywords that people are likely to type into Google will help relevant content show up in search results. In fact Matt Cutts of Google recommends that you think of keywords that searchers would use and include this in the title of your article. Google is constantly getting better at filtering out the sites that try to manipulate the rankings with tricks. Part of good SEO is generating remarkable, useful, and interesting content that people want. This is good for users who are seeking information or entertainment.
While there definitely are a lot of bad apples who will break any rules they can to get ahead, there are these in every field.
However, it is very difficult to change perception once it has been established. The best thing good SEOs can do is educate people on how SEO can be a powerful and legitimate tool for companies to cost effectively market their product or service.