I get your point. And I don't doubt Honda's engineers. Like I said, I'm not a chemist (or engineer), which is why I came here for help sorting through all the information and pervasive marketing chimeras out there. It just seemed to me that the manual might list minimum requirements, as for example it does for the gasoline (Min. 86 octane), which would imply that better wouldn't hurt. (Nobody sells less than 87 oct. around here anyway.) Of course gas and oil two are two different discussions; just using that to make a more general point.
Having said that, Redline does NOT in fact display the API emblem on their bottles. Instead, it says "recommended for API ...." And they state the API applications for their different street oils on their website:
http://www.redlineoil.com/pdf/4.pdf
I assume (chagrined) that means they are not API certified. Does that also mean necessarily that they do not meet the API specifications, even though they list those specifications? How would one find out? (Presumably not from Redline.) Or if they DO meet the specifications, why wouldn't they be certified? And why are so many people so enthusastic about their street oils? Just ignorance and a strong racing reputation, as Buster implied? Stranger things have occured....
You've definitely pointed out reasons for skepticism, which is helpful.