Okay, first off, I could have stated that I did check the wind speed with an anemometer, but I didn't. I said that I estimated the wind to be in that range with stronger gusts. I stand by that. Technically you are right that wave height is often overestimated by double, but here again, I specified from trough to crest--not the true wave height of maybe four feet.
When the average paddler uses a bit of hyperbole when telling a tale of a paddling adventure, it is to emphasize the magnitude of the situation and make the story more graphic. If it suits you better, just reduce everything by 150 to 200 percent and have a nice read.