Why gay marriage makes no sense

What is it about gay marriage that makes it an imperative, much less neccessary? It just doesn't make sense.

If I may, let me utilize an analogy that involves motorcycles, and cars.

Not too long ago, motorcycles decided that it no longer was sufficient to registered with the state department of transportation as motorcycles. They wanted to be registered as cars instead. Now the cars were certainly perplexed, and a little bit miffed at the idea. After all, motorcycles had the exact same access to every bit of the public roadways as any car, and in some cases of heavy traffic, maybe a little bit better. Why then change the registration? The motorcycles countered with the argument that in spite of the fact that motorcycles weren't anywhere close to the form and function of a car, they wanted to have the same designation to make them feel 'equal' to cars. Somehow, just the title would give them a legitimacy they felt they heretofore lacked. The cars countered back, saying that having a car registration would no longer have any logical meaning. After all, cars have always had doors, roofs, 4 wheels, and all that. It's what made them cars. Motorcycles have had none of those things, ever. "Shouldn't cars be defined by what they actually are, and not what somebody else wants them to be?",  they asked. "No.", said the motorcycles, "Its 'cars' or nothing.". Well, they took it to court. The judge flat out told the motorcycles that motorcycles, though certainly not any better or worse a vehicle to have out on the public roads, they weren't cars, and never would be.

Motorcycles ain't cars.