When you are a creator of a program you tend to protect it like it was another child. It doesn’t matter if you are a big company or a small one, when you create a program to be distributed to the masses it is probably your pride and joy. This is why some owners of programs get upset when flaws are pointed out in the applications. While some owners of applications can take a healthy amount of criticism, some cannot and they will find that their lack of patience will harm the application.
It is a good thing when the people who buy your applications point out the flaws in it. It is especially good when they point out the security flaws in your application. You want to be able to fix those as soon as possible. So you want to encourage your users to reports problems such as this. If you get defensive every time someone tries to point out a problem then you will never get it fixed because people will be less willing to point them out. Over time this will affect the stability of the application and you will find yourself with a product that no-one wants.
Sure, there can be people who are a pain in the butt and they just want to point out any problems that they can come across. No matter if it is large or small they just want to bother you. These are the type of people that you ignore. Most of the people who point out flaws in the application are not like that though. Most of the people really like your product and they want to help you make it better. These are the type of people that you need on your team.
When you have a new app that you are releasing to the world be ready to hear both the good and the bad of the product. If you listen to the constructive criticism it can only make your product safer than it already is.