Dual stance

I was wondering about the dual stance Jeff Crowe took in the first test. Or how could have he let off Lara was his behaviour on the field and fine Sehwag for celebrating a dismissal without appealing to the umpire. Siddhartha Vaidyanathan writes about this double standards here. If Jayawardene was fined, even after apologising for knocking over the stumps in frustration, how can Lara be let off?