You make a good point but I don't think you understand the NOP haters. There is basically ZERO reason to hate the NOP for their performance. It's incredible.
The people that don't like the NOP because they think they are dirty. What has sports taught them for the last 20+ years? If something seems too good to be true - whether Lance, Bonds, Ben Johnson, etc - it was too good to be true.
So I don't think Levins double is going to change their opinion at all. I think it will just make them double down.
In my mind, there are two possible views of the NOP for most people.
1) What you state. Alberto is truly amazing and figured out a way to develop speed that no one else has.
2) They have a pharmaceutical edge - that may or may not be legal - that makes them do stuff others can't do.
(The third view would be they collect the very best talent but I certainly wouldn't put Mo Farah or Cam Levins in that category before they got to Alberto)
The lovers are in camp #1, haters in camp #2.
The people in camp #2 watch that race and think, "What in the hell besides pharmacology could Alberto have figured out that allows a man to pull of a double like that in less than 30 minutes?" If anything, Levins double might make them more of haters as they just don't see how a double like that is physiologically possible.
It makes sense to me that their are 'lovers' and 'haters'. Alberto has clearly either figured something out that no other coach has figured out or something medical related is going on. Most people have 1 of those 2 views.
It's kind of like how people view the Patriots. They either are smarter than everyone else or cheaters.