One problem with the argument from design

Apologists and creationists love the argument from design: Since the universe has been "clearly" designed, there must have been an intelligent designer that made it.

I'm not going to scrutinize the major fallacies in that argument, but instead I'm going to concentrate on one detail that I just noticed: They always talk about a designer. In singular. Always, and without fail. But why?

Let's take a typical form of the argument from design: If you find a device, like a new kind of computer, and you examine it and study how it works, you come up with the conclusion that it was designed. By the apologists' logic there must have been a designer. In singular. One intelligence that designed and built it.

But we know that's not true. Modern computers are the product of several hundreds of years of work made by thousands and thousands of people, each contributing a tiny part to the whole pool of knowledge required to build a modern computer. There is no one single person who designed and built a modern computer from scratch, with no previous knowledge nor expertise. As the adage goes, "we stand on the shoulders of giants," meaning that all the knowledge we have today is based on the work of thousands and thousand of people from the past, each contributing to this pool of knowledge with their research and experiments.

In other words, a modern computer can be classified as the design of thousands and thousands of people.

So why, exactly, is the alleged design of our universe always attributed by apologists to one intelligent being?

In fact, any argument that they could give for this could also be applied to reasoning why a modern computer has been completely designed and built by one single person (with no previous knowledge of anything that's required.) For example, if they appeal to Occam's Razor, ie. that it's simpler to assume that one mind designed the universe, the exact same argument could be applied to the design of a computer: In other words, that it's "simpler" to assume that one single person designed and built the modern computer. (And, in fact, when we do this, we immediately spot one flaw with this argument: The alleged "simplicity" of assuming one individual designer is a flawed concept. It's a misapplication of the Occam's Razor principle. One single designer is actually less believable than multiple designers. The proper application of Occam's Razor would be to assume thousands of designers. One single designer would require a lot more evidence.)