NO ONE IS TRYING TO EXONERATE DIANE SHULER! NO ONE IS "GIVING HER A PASS."
Please read the posts above.
When it comes to the concepts of "wrong" or "responsible" or "guilt," most people view these things on a continuum. For example, at 0, we have person who has done nothing wrong at all and cannot be blamed. Perhaps at 4, we have someone who has a horrific toothache or migraine who felt they MUST seek relief, and the only thing available is vodka and weed. At 7, we have a woman who has gotten incredibly pissed at her husband and her circumstances and decides to take the edge of with some vodka and pot, figuring she'l handle it and get everyone home safe. At 9, we have someone who, do to repressed rage, a horrific catalyst such as infidelity or feeling betrayed by a brother embracing a mother viewed as unworthy, or some other emotional trauma, committing suicide in order to end it all, willfully and knowingly taking 7 innocents with her. Perhaps at 10 on the scale would be taking her kids and nieces on a camping trip and slitting their throats while sober and filled with calm resolve. The epitome of evil and all agree could be the worst the human experience can deliver.
As far as DS is concerned, on the far left of the continuum, we have 0; meaning that Diane has Zero culpability or responsibility for what happened. Those who insist that she could have had a STROKE (which inexplicably nevertheless resulted in a positive drug and alcohol screen on two different tests) which caused her physical symptoms have put DS's "wrong" as ZERO on the continuum. And Nova, there are those who have postulated this possibility, as well as the McDonald's one, which, contrary to your all caps declaration,
does mean that there are some who are looking for a reason to exonerate her. Who would disagree that someone who has a STROKE while driving cannot possibly be held responsible for any accident which happens as a result? Also at 0 are those who surmised that perhaps a McDonald's employee spiked her orange juice. This would certainly put her at 0, as if she had been slipped drugs/alcohol in her juice or food, we cannot blame her for that, can we?
We have those who look for some other physical condition which would cause DS to desperately guzzle vodka and smoke weed. Now, this doesn't absolve her completely, but it does put her more on the sympathetic end of the continuum when compared with the other examples I listed at 7, 9, and 10. And people really, really want to put her on the more sympathetic side, witnessed by the many who have actually given credence to the toothache theory, the gestational diabetes (two years after giving birth) theory, the migraine theory, and even the more far-fetched theories such as high blood alcohol content due to "charring" caused by the accident.
People really want to give DS the benefit of the doubt, which is simply so very different from most other DUI accidents, even those which involve mothers, intelligent and accomplished professionals, or others who weren't known to be obvious bad people or drunks. I find this to be notable.
The most logical reason for DS drinking and smoking herself to oblivion is something do with with her marriage, her emotions, despair, pressures of carrying way more than her share, her soon to be damaged reputation for being "perfect," etc., which are typically the same reasons ANYONE does such a thing. Looking for a physical ailment which explains her actions makes about as much sense as taking a 2.5 hour detour to take 3 kids to Long Island. Why look for such a circuitous route to explaining this, rather than the ones which are plain as the noses on our face; that have NOTHING to do with a stroke or a toothache or a miraculous coincidence of identically wrong drug screens performed by separate labs, or my favorite, no alcohol consumption at all but the high temperature of the fiery crash charring her flesh and causing her blood to produce high levels of alcohol in her blood, urine, and vitreous humor?
We don't know specifically what set her off, but it probably has much more to do with her being a fallible human being than any other extremely unlikely physical ailment. I get that people are curious whether it was the discovery of infidelity, a fight with Daniel, or suicide; I am as curious as the next person. But I always go back to Occam's Razor, that the simplest explanation is usually the correct one, and the words of Dr. Spitz, Daniel's independently hired coroner consult:
"the question of the alcohol will always prevail."