It was probably looking to take out a few soccer moms
They looked pretty scared. It was imposible to tell what they were saying because of their language. If I had been there my biggest worry would be about flying debris taking an eye out. The vortex did not seem conected to any deep moist convection, but if it had been I would have been more scared. I imagine that this dust devil spun up in a very deep mixed layer, with very steep superadiabatic lapse rates near the ground. I doubt that it would have reached such an intensity had it not managed to dwell for tens of seconds over smooth tarmac. Any roughness or trees, and they just fall apart.
I would say wind speeds topped 55MPH for a very brief moment. Since the F-Scale is based upon damage only, and it only did very minor damage to portable structures only, I would have to say very weak F0.