I agree that the merger will undoubtedly hurt their cable customers, for a wide variety of reasons. However, it is not an issue for all Roku owners. It only affects the group where these two conditions overlap - and I would question how many people that really affects. Do many people really use a Roku if they have access to cable?? And not have another device that can do the same, such as a game system or smart TV? (I bet even some of those complaining are simply sharing an account with friends/family anyway. I know I'd gladly mooch off someone's HBO subscription if I knew someone well enough to ask.)
For Roku owners like myself, who have neither Comcast nor Time Warner and have no intentions of subscribing to either, it doesn't matter that much.