I'm entirely in agreement.
It's the stridence of the "NS knew" people I don't agree with. The police investigation lasted nearly 5 years, if she was as up to her neck in it as people are maintaining, I think it's inevitable there would have been some legal consequence.
The actual Treasurer of the SNP, Colin Beattie, was also arrested, interviewed extensively, then released without charge and later told he was no longer part of the investigation. If you'd expect anyone to have twigged something was amiss, or to be part of some sort of conspiracy to embezzle, it would be him, but apparently the Police are entirely happy this was Murrell acting off his own back.
As you allude to, there are clearly short-comings in how SNP finances were being managed, and a lack of scrutiny/good practice, it's the seeming inability to accept that one opportunistic individual took advantage of this I don't really understand. I've had access to the funds of an organisation in a past role myself. I had limited spending powers that I could use with impunity. There was nothing stopping me theoretically abusing this other than my own sense of morality and the fact audit might, only might mind you, have detected it at a later date. It's really not all that surprising to me that a less upstanding individual might succumb to temptation in similar circumstances, and especially so when the vulnerable amounts are far larger than anything I could ever have got my hands on.