Don't take too seriously any attitude you see in these talks. They are preaching to the security converted and trying to show off a little. If anyone really treated clients that way (or cared that much, for that matter), then they would be in the wrong profession.
In reality, pentesters are hired to report on the security status, recommend better practice where relevant, and then back off. As mentioned above, it all comes down to money. The client company gets to decide whether fixing or leaving problems is most cost effective. It's simple business. Sure you get clients making questionable decisions, but that is their business.
Certainly, don't let anyone's attitude dissuade you from getting more involved in security. You get all types in all professions, but I suspect anyone causing trouble for someone earnestly joining the industry would be quickly shot down by the majority.