Allright, I believe that the correct equation for the JD-standard deviation is:
For an individual bet, sqrt(p * (1 - p)) is the expected standard deviation of the chance to win. The expected standard deviation of the return is obtained by simply multiplying by the expected return, which is 0.99 * b.
Summation of standard deviations for independent random variables is done through taking the root of the sum of the squares. Each term is multiplied by how often it occurs (c).
That brings me to the numbers obtained from the dataset posted by dooglus:
# of bets = 33,257,221 (currently posted on site: 33,524,569)
Total BTC bet = 556,351 (currently posted on site: 557,909)
Expected BTC return for gamblers = 550,787
Expected house profit = 5564 (if only ...)
Expected house edge = 1.0000881%
Expected standard deviation of amount returned to gamblers = 2754
Current house profit is at -228 BTC, which is 2.1 times the standard deviation away from the expectation value. If the profit follows a normal distribution, the probability of this deviation occurring through sheer chance is approximately 2.5%.
Conclusion: The site has been very unlucky, but the deviation is not large enough to be implausible.