Agreed about Ditko's character. (Ditko is perhaps the only non-closeted Ayn Rand fan that I admire for consistency.) But his case isn't really all that clear-cut.

Courts are notorious for focusing on very simplistic cut-and-dried demonstrable facts, and the creation of a popular character called Spider-Man is just not in the least cut-and-dried. Legend has it that Lee "thought up the name", but there's nothing unique or original about the name itself. Legend also has it that Kirby did the first treatment based on Lee's name, but that original treatment was an awful lot like the Simon-and-Kirby Tommy Troy-Fly character. There was also Spider-Man-like pages found in Joe Simon's archives, circa 1956. There are too many cooks in this particular broth.

Of course for anyone who wanted to take the time, they would understand that the reason that Spider-Man is a billion-dollar character and The Fly is a thousand-dollar footnote is due to Peter Parker and his situations, not due to his ability to walk on walls. How much of that is attributable to Ditko and how much to Lee is an argument no one will ever win.