Have you actually watched the presentation? If not, I encourage you to do so. Category theory and abstract algebra help us understand what it means to build composable and reusable software components with well defined semantics. There is already ample focus on algorithms and discreet math at university courses, but very little of the above. This is despite the fact that modern software development is becoming more about composing existing code and less about reimplementing classic algorithms. So given the already ample focus on the topics you suggest, I think we can forgive Phil Wadler for giving a very brief glimpse into a promising subject that most hackers would dismiss as obscure/irreverent.