Starships join Genesis as symbols of technological and scientific innovation, exploring how both can either assist or harm humanity in our evolution…

…but, unlike Genesis, the starships aren't total symbolic downers.

Instead, you can think of them like social media; they take on the personalities of the people using them. In this case, their captains.

Consider the Enterprise. For Kirk, the starship represents home, family, and friends. He even refers to it as a "house with all the children gone" in reference to Saavik and David's departure.

As Adam Roberts points out, "the Enterprise is amongst the most humanized examples of spaceship technology" (Source). It's a part of the family, and just as the crew supports each other in their search for Spock, the Enterprise shows technology supporting mankind's endeavors. In the Original Series, it also supported mankind's efforts to "explore new life and new civilizations."

Then there's the Excelsior. A slick, futuristic bit of tech, the Excelsior represents the ever-moving march of technological advancement. Typically this is a good thing. More advanced technologies allow us to perform greater feats, like how advancements in processing power have allowed us to carry computers in our pockets.

But Captain Styles sees it as nothing more than a machine, and as a result, it lacks the humanity of the Enterprise.

Let's also consider the Klingon Bird-of-Prey. This starship was made for combat, not exploration. The design of the ship keys us into this right away. The giant shoulder-pad bulges present it like a bruiser, and the wings make it look like its swooping in on you whenever it's on screen. Even the name, "Bird-of-Prey," has violent connotations. This ship symbolizes that some technological advancements are meant to hurt rather than uplift others, making it an excellent symbol for Kruge and a perfect counterpoint for the Enterprise.

Finally, there's the USS Grissom. Like its captain, the Grissom is pretty effete as evident by the way it…blows up? Yeah, that's really all we got for this one.