I agree with you... sort of. RacingJunk, in my opinion, is a great asset for racers to help other racers, and get help from others. I've asked questions of people looking to sell cars, and I've always had positive results.
I don't BS them though. I'll tell them that I am unable to purchase their vehicle, but if they would be able to help me out on my own build by answering a question or two it would be greatly appreciated.
A simple question or two should warrant an answer. A build sheet or step-by-step is different. Courtesy is rapidly disappearing in the world around us. I'd hate to see it leave the world of racing, and that extends to both those asking the questions, and those getting asked.