That is not necessarily true, the top end bikes are laid by hand, but the mid to low level ones use a mold, see: https://cyclingtips.com/2011/08/are-...created-equal/ This is what that site says:

Open Mold Frames

"An “open mold frame” is a mold which the factory owns. They can sell that frame to anyone they choose. The brands who buy these open mold frames don’t own or control the design, engineering, or material selection for the products they’re marketing. Generally, they specify the paint and logos. You’ll see some of the smaller brands with identical frames from one to the next. This is often what you’ll be getting when you select an inexpensive carbon frame or component. These might be perfectly good, and they might not be. You just don’t know.

Many name-brands will purchase the molds they use and own them. That is the brand’s IP and the factory cannot sell that frame to anyone else."

And this video at 3:35 into it shows a mold: and this video:
Keep in mind to that regardless of how much hand work is involved most CF frames are made in China who employs workers with an average wage of $27.50 a day, so really any hand labor being done is being done dirt cheap.