I think the root issue facing theorists these days is their confusing the map with the territory. Just because the map is internally consistent does not mean it IS the territory.
That being said, I think crackpot ideas are rooted in confusing the map with the territory, and speculative ideas do not.
For instance, thinking the number "5" is real and can run down the road is crackpot. Speculative is thinking there can be "5" chairs in the middle of the road, regardless if they are there or not.
So speculative can be right or wrong, crackpot is crazy and does not understand what is happening.