Any reasonable, honest observer would halt the discussion immediately at the point they realise the TPP is being negotiated in secret (with the public and even political representatives kept in the dark over TPP contents over the many years it has been negotiated).
That corporate interests have unfettered access to the text and negotiations and democratic citizens do not is evidence enough of exactly whose interests are being negotiated.
That the text and all associated material must remain secret for four years after the negotiations have ended (whether successful or not) shows the level of trust negotiators have in engaging with an informed democracy.
It gets to the heart of the sickness of secrecy that has infected whole swaths of our democratic institutions. Trying to guide discussion towards whether people are 'pro or anti trade' is risable misdirection or wilful ignorance at best.
The TPP is a full-frontal assault on democracy and national sovereignty from what we have learnt through leaked draft texts, and its contents are highly likely to represent a backdoor check-mate across internet censorship, DRM, copyright, and many other issues this community cares about.