Avoiding pissing people off is a basic ethical concern, which is at least as important as making money. Obviously it can't be totally avoided, but you try anyway. If you can't make more money without pissing a bunch of people off, you should consider changing your business.
This isn't about a bunch of people. Remember, we're talking about so few people that they don't even make a blip in any of your metrics. If you're getting angry replies or all your emails are deleted without being read or lots of people are unsubscribing, yeah, that's bad and you should think about what you've done wrong. But that's not the situation we're talking about here.
Again, McDonald's pisses off millions of vegetarians every single day. Would you say on that basis that they should go meatless? Should churches close to avoid pissing off militant atheists?
The point is not that you should be callous about offending people. Obviously it is better for all involved to make people happy, and that should always be your goal. But the point is that one or two guys saying "I'm so angry!" on an Internet forum does not mean you've failed. No matter what you do, even if it's pure charity work, you'll eventually find someone who gets upset about it. All you can do is apologize and offer to unsubscribe them — it's not rational to throw your business away on that basis.
