GoPro had been downsizing to return to profitability. Most likely they looked at the number of people using the Apple watch app, considered the cost of continuing to develope and support it, and determined that it was too costly. I don't know why this makes you feel "disrespected" but it's not an affront directed at you.
This might come as a big surprise, but GoPro is a company. Not only that, they are publicly traded. There responsibility is to serve the share holders as well as their customers. Since GoPro has not made a profit in the last several years, they are required to make cuts to non essential departments. With less than one thousand employees world wide, they aren't that big to begin with.
GoPro knows exactly how many people have downloaded and are using the watch app. They wouldn't have discontinued it if it was a widely used app. However, with that being said, I'm sure that if they can return to profitability, there is a very good chance that the resources will be made available to continue the app again.
