It's interesting reading the back and forth here on aborts.
Let's make it a bit more simple with some common sense. In general, after numerous CRM studies, it is better for the CA to make the abort decision. This is similar to how it's typically better for the FO to fly in the event of an abnormal and the CA to manage the situation.
As something arises, call it out. They will make the decision, which is normally correct. Most of the time (how often do we abort anyways? I've done 2 in 10 years and they were both low speed), this works best. Seeing it in the schoolhouse countless times, I tend to agree.
But of course, there is clearly the wrong "GO" decision (or lack of decision). It's still pretty simple... if you see it becoming unsafe really quick... CALL IT OUT. "ABORT ABORT ABORT."
You're going to have to explain yourself later (as will the CA), but that's better than being dead.