zahavasdad, the people who made the app actually claim that you should be permitted to watch TV on Shabbat on their website. I quote their spokesperson/web moderator Yossi Goldstein in a comment section response to someone using your very argument:
“Why is your kids watching Curious George on TV on Shabbos any different than you reading them Curious George from a book? The only difference is who is providing the voice and turning the pages, Logically if you think about it, there is absolutely nothing wrong with watching TV on Shabbos, as long as what you are watching you would anyhow see on Shabbos.”
This whole thing is just another sad example of how far off people have gone without a Mesorah and without a Rov.