Probability does use some tools from combinatorics and vice versa, but the two subjects have vastly different goals.
Similarly I find it highly questionable whether combinatorics is "clearly more relevant to general programming". In fact, what is "general programming"? Probability theory pervades all of Computer Science - from probabilistic algorithms (QuickSort), through cryptography, optimization algorithms (genetic algorithms, simulated annealing), networking (information theory, queuing theory), machine learning, the list goes on and on. For business programming, statistics (based on probablity theory) is crucial. Some of those applications include combinatorics, but I find it harder to find such a long list of applications of combinatorics being used without probability theory - it is a more specialized field.