I came up with the hypothesis when I considered that they only made Clovis points for a time and then they went back to making easier spear points. Of course, the fluting helps in attaching the point to a shaft. However, there is no sign that they had too much trouble attaching later points to the shaft either.
They could test my hypothesis by looking for toxins in the flutes. Maybe a few molecules remain.
I still think that Clovis points had something to do with the extinction of the megafauna. There is certainly a temporal connection.
As for the disease hypothesis, it would be unusual if one parasite or pathogen wiped out multiple species.
No doubt that the Clovis point hastened the demise. It is just counter intuitive to consider large blades and poison when poison generally negated the need for initial stopping power.