Again, think of it as a single global namespace. When this particular fellow was named, the other David Duke hadn't hit the news yet - but when the name "David Duke" did become famous and recognizable, there was a namespace collision. That can happen to anyone, especially if your last name is common.
Google makes names easier to "recognize", and the Internet's vastness increases the total amount of "fame". So in the age of the Internet, you want to pick a name for your child that is likely to be and stay unique.
If you have a common last name, a first name that is very rare but not unique, doesn't look strange, and is easy to spell and pronounce, would be ideal.
My problem with your argument is that words are "easy to spell and pronounce" because they are common and people have experienced them before.
When I said people are unable to recognise names they haven't heard before I mean that literally. They try to coerce it into one they've heard before and either succeed and call you something random or require you to repeat it 3 times before they are convinced they're not just miss-hearing it.
The only way to get something easy to spell and pronounce that is rare would be to compound common forms. Frankly this is exactly what the middle name does.
That said JoHadRon is globally unique (at least according to google) and has useful short forms. I may change my name.
Oh, well. I'm sure George Graham will want to change his name anyway at age 21 in order to outrun all the hideously embarrassing Internet posts he made at age 12, should the present world last so long.
Maybe you want to give your kid a highly anonymous first+last name, and a unique second+last name, so they can switch to using second+last once they grow up.
PS: I know a poor guy who happens to be named David Duke. (I suggested he go by Dave Duke.)