No, they’re built to make cycling safer and more comfortable.
We have motorways for cars (or are you suggesting those should be used by cyclists, too? How do people cycle from Barcelona to Toledo, for example?), sidewalks for pedestrians (at least in many parts of the world), why not have dedicated infrastructure for cyclists?
If what you say is true, the Netherlands is doing it wrong with their “Separate where needed, mix where possible” policy (https://bicycledutch.wordpress.com/2012/08/09/separate-where...)
That may be true, but (IMO) requires more proof than a comment on HN.