Sometimes people read 'We're not interested' as 'We are interested', and sometimes as 'We are not interested'. Usually it depends on what the reader wants to hear.
Personally, I think Cazorla might be the former, M'Vila probably the latter. That's based on the more thorough rationale he gave around the M'Vila question, my feeling all summer long on what's actually wrong with the team, disregard for ITKs, and how I think Wenger perceives his squad.
Coincidentally, it's also what I want to hear.