There was enough written about this specific issue to suggest it might be political opportunism. Of course it's also not fair to not let people actually change their mind.
Respectfully, there are a couple examples of loaded-ness in your original comment.
>> Clinton's de-endorsement was probably not genuine
From the article you linked, this is what she said "Although Clinton had traveled the world in support of TPP as President Barack Obama’s secretary of state, she told the “PBS Newshour” that the final agreement didn’t meet the “high bar” she set for the pact."
Sounds like she still liked the idea, but the agreement wasnt to her liking.
>>My main point is that an issue that was popular on the left (enough for Clinton to flip-flop on) seems to now be mostly the voices of the left criticizing the withdraw.
Again, if more info came out and people changed their mind, you seem to be villifying it and declaring it a "left" problem. (which it may be, but you're asserting with an anecdote on what you've noticed)
https://www.politico.com/story/2016/10/hillary-clinton-trade...
Maybe flip-flopping is too loaded of a word and I shouldn't have used it.