That's the *only* reason If you launch from KSC and head due east, you're at the same inclination as the moon. At any other latitude (except the duplicate one in the southern hemisphere) a fuel expensive plane-change maneuver would be required for a trip to the moon. From KSC, you just wait for the moon to pass overhead, which it does once each day, and launch due east. Voila, you're in a parking orbit.

Other concerns, like proximity to water, are available pretty much anywhere on the east coast. They could have built KSC a little farther south and done the plane change maneuver at launch - that's cheaper than doing it in orbit. But the best option in terms of fuel use is to have the launch complex exactly where it is.

To get the ISS, the shuttle has to head a little farther north. I don't remember the exact inclination, but it's higher than the moon. Basically, the ISS's orbit is a compromise between what NASA and the Russian space agency can easily reach. If we had built the ISS ourselves, you can bet that it would have been in the exact same inclination as the moon.

Edit to correct this: you just wait for the moon to pass overhead, which it does once each day

What I mean is, the *orbit* of the moon passes overhead, or more accurately, the earth rotates putting KSC under the moon's orbit.