Since we're talking about freeciv, civ2 on deity is pretty easy if you know what you're doing. It's not even a forced way of playing, you can decide to win with just one city, or you can decide to spam cities with less than 3 population to avoid population penalties, and there's many other strategies.

If you don't know the game well enough to win at the highest difficulty, it is not degrading to play at lower difficulties to learn the ropes while still enjoying the game.