They don’t consider how international politics will shift.
If you have investments in the US, in whom would you be more likely to have normal relations? Hillary or Trump?
Foreign power will be much more likely to use force against Hillary, than against Trump, as a simple matter or course.
They know that if she able to circumvent all forms of national governance, she won’t be trustworthy in any agreement.
I'd wager this is actually foremost in their minds: is the TPP most likely to "pass muster" with Trump, or with Clinton?