"Builder" used to be a compliment. It was the title of someone who spent hours working out each little detail. Agonizing over the best place to run the wiring harness. Making sure the correct grade of bolt was used. They were accomplished welders, body and paint experts, mechanics, electricians, and often engineers, all in one.
Now it is an insult. Any twit who can paint a bike flat black and put a sprung seat on is called a "builder". That is all it apparently takes to qualify them to be called a "builder" in a magazine or on one of the hipster bike websites.
98% of the "custom" or "shop built" bikes out there are pure crap. The "builder" bought a junk bike, stripped off all the broken bits, ground off all the mounting tabs and most of the rust, shot flat black on everything, stole some parts off another bike, and went to an abandoned warehouse for a photo shoot. The bike is not street legal and probably doesn't run. Nobody would want to ride it anyways because the "builder" couldn't put 2 layers of foam for the skateboard seat because they didn't have enough leather from the jacket they bought at the thrift shop. Those trick gold USD forks are bottomed out because they have nothing inside them. "The engine is in good shape so they didn't open it" = they have no idea what is inside there and are afraid too look as they might have gotten their hands dirty.
But, all that is irrelevant when posing beside the bike as long as one is wearing a plaid flannel shirt and has a scruffy but well waxed beard. Then it is cool...
Don't ever call me a "builder". You might just find yourself on the ground...