Lets better return to the subject.
I agree with your overall conclusion that it's possible the attack was carried out by some special agencies, and that it might be reasonable from their standpoint.
But the chain of causality you draw looks to me as an arbitrary fantasy; or to say better, only one of many possible explanations. It puts together several unverified assumptions - statements which are not 100% true, but only probable to some degree.
The probability of all that happen together is a multiplication of all the probabilities, and therefore a small number.
There is no evidence that Kaspersky Labs work for Russian intelligence. Yes, there were articles where journalists say "oh, he worked in KGB, so we can imagine they still cooperate". The fact we can imagine something doesn't mean it's true. All we can say for sure, Kaspersky Labs maybe work for KGB, or maybe not (including they work for somebody else, why not imagine this).
Does Russia want to support Iranian nuclear program, up to providing cyber security? IMHO unlikely, but again - maybe yes, maybe no.
Even if Russia decided to support Iran, there is no proof Russia employed Kaspersky and not a proper department of intelligence service - maybe Kaspersky detected stuxnet fairly, during their anti-virus research (their primary business, isn't it possible)?
Even that stuxnet is an US intelligence creature is not a 100% fact; there were strong evidence to support that, but we don't know 100%.
0.1 * 0.2 * 0.4 * 0.9 = 0.0072
Put your own number if you find your assumptions more realistic:
P(Kaspersky Labs work for KGB) = 0.8
P(Russia wants so provide cyber security for Iranian nuclear program) = 0.5
P(Kasperky Labs detected stuxnet specifically because
of intelligence order, as russian intelligence
has no other cybersecurity departments) = 0.5
P(stuxned is developed by US intelligence to attack Iran) = 0.95
Anyway, the combined probability of 0.8 * 0.5 * 0.5 * 0.95 = 0.19