technically not cheating
it's taking advantage of poor game design, therefore it is not against the rules of the game.
framing the experience
whether or not a degenerate strategy is a "proper" way to play is based on how it is framed.
ecosystems
when designing a game, the game designer has to be on the lookout for flaws that could lead to these strategies and patch them out. if the means to win a game only exists in a singular way, then it has poor game design. though, there is a fuzzy line between degenerate strategies and imaginative ways of winning.
degenerate strategies can be countered by the community of players. though sometimes game designers need to get involved to mediate the problem.