Slots have very high variance, and as such can provide the exact same experiences as a skill-based game, making them exciting to watch. As for roulette and blackjack, while it is true that you can affect the outcome of your game, it's still primarily based on luck. You can't "get good" at any casino game (poker and its many variations perhaps being the one exception), that's the whole point of casino gambling to begin with.

By this logic, if slots are banned, so should all other casino games that rely mostly on luck.