It's getting to look rather desperate on the detractors side.
It is hard to not be skeptical when the claimaints tell us about superior skills, yet aren't winning MMA tournaments (say UFC) using their amazing internal skills (that we can distinguish from regular ol brute force external skills).
Use your brain people. If someone is claiming that no matter what they cannot be pushed over, shouldn't they enter a sumo tournament, a taijiquan push hands tournament, and be the perpetual winner for the rest of their life?
Seeing tournament results would be infinitely more effective than spending $ and time to just see static demos with 'play nice' rules and dozens of parameters (which if varied, the trick probably wouldn't work), to assess martial efficiency, don't you think?
The Hardens and Sigmans of the world wouldn't touch that route with a 10 foot pole, however. Else they'd have done it by now to shut up all the "detractors" (ie. people who are skeptical of their claims).