Personally, I'm not offended by the porn industry. However, I can understand it when people are. It's a scuzzy industry. I'm sure whoever you're talking about was being over the top with their comments, but I can still understand people being outraged by the industry, and not having much, if any respect for the people in it.
Ask yourself if you would be totally cool with your daughter/sister/mother doing it, and if your answer is "hell no!" like most people, wonder why that is. The answer is because you find the profession repugnant and disgusting, and wouldn't want it to effect you personally, by having a relative involved in it. You may not express that sentiment as bluntly as the person you're talking about has, but deep down, most people are put off by it...when they're not jacking off to it.