People keep repeating this line with no evidence. I've been around for a number of international treaties and this is the first one I recall where the #1 issue is how secretive and un-democratic the process is.
Of course there are always backchannel discussions but with the TPP there has be little indication that ANY of the initiatives are actually being driven by the needs of the electorate.
When my elected official couldn't even see a copy for years (even in secret) and then was only able to when it was basically an all-or-nothing done deal about to signed something is very, very wrong.