Battles are much more exciting when you can see both sides at once.
The answer much of the time is probably simply that long- and standoff-range combat just is not flashy enough when it occurs at the distances spacecraft are liable to engage each other at. Even in popular media, naval battles tend to take place in flashy spates of gunfire exchanged between aircraft strafing ships and being pursued by other jets only seconds behind. This sort of combat is much more exciting-- much "sexier"-- than what is more liable to be the case: missiles being fired from tens, hundreds, or thousands of kilometers away, travelling-- probably drifting most of the time, save for course corrections-- for minutes or hours, then exploding near their targets, hoping to strike them with high-velocity shrapnel, if they aren't defeated mid-flight, which they very likely could be.
Space is huge.
In space, this dawdling is made much worse by the fact that ranges are liable to be on the order of thousands (solid munitions) to hundreds of thousands (laser weapons) of kilometers, orbit-to-surface bombardment aside. This would either involve a lot of travel time on the part of craft and munitions to their targets, or would be extremely difficult to frame in any cinematic way because only one side is properly visible. Conversely, the amount of time it would take a laser to realistically strike its target at that range makes cuts difficult and unwieldy, which is why you see "slow lasers" in franchises like Star Wars so often: a narrow ray shining across an entire battlefield at once for a short moment doesn't have the same cinematic energy that a glowing bolt of death careening (that is, slow enough to have perceptible motion) through space does. Also, it's more riveting if they miss sometimes.
More exotic sorts of weapons like transwarp munitions or FTL missiles can bridge this 'cinematographic gap' by cutting the weapons' flight time down and adding an element of unpredictability to their appearance on the battlefield, but are still difficult to depict correctly due to their speed, to say nothing of their physical practicality. Alternatively, consider this somewhat spoilery example from the "Gateway Shuffle" episode of Cowboy Bebop, or the Starkiller shot from Star Wars: The Force Awakens.
Having things to look at matters.
Sometimes long-range battles can be shown somewhat realistically by exchanging white-knuckle dogfighting for volume of fire. The animated adaptation of Legend of the Galactic Heroes does this fairly elegantly, but a pitched battle with thousands of ships in geometric formations doesn't generally have the same visual appeal as a stomach turning race through an asteroid field.
Quick, twitchy skirmishes between ships only a few dozen lengths apart are by far more visually engaging than slow tactical battles fought over light-seconds.