As others have pointed out, Allan's "reply" is quite the non-reply with the lack of concrete proof and evidence of the supposed "copyright infringement". What I personally found interesting, however, was Allan's initial reaction to the Flat UI Kit on Twitter: "Has nothing to do with us. Very distasteful."[1]

Later on, after the pitchforks had showed up, he tweeted the following: "It's neat that someone made a flat ui kit"[2]

That tune sure changed quickly!

[1] https://twitter.com/Allan/status/308937462221254657

[2] https://twitter.com/Allan/status/309346292902014976