Responding in detail to ‘anonymous sources’ or article writers like Esptein is kinda stupid.
Every time anonymous source(s) that blows to make a presidential candidate jump would make the candidate their puppet.
Making one's position on a critical issue clear is always the best policy, unless a candidate has something to hide.
Nothing you can say changes the reality that clarifying is the best policy. And Walker's campaign did respond, but in a vague and evasive manner.