I understand it's a free service, that I'm not a paying customer, that I was wasting a resource by not actively using the service.
It's distressing to be given something by someone with power, to use the thing and in small ways rely on it and enjoy it, then suddenly it's taken away. I hope every inactive person gets their notices before they lose their data. I didn't for my Voice number and now I'm trying to sort out all the services I have tied to it.
Again, I understand Google has all the power. I had no leverage and shouldn't have had any expectations for how I'd be treated. However the amount of goodwill I have towards Google is rapidly approaching zero. I've read a thousand messages here saying variations of, "don't rely on Google, you will get hosed eventually". This (deleting inactive accounts with no option to opt out) is the kind of treatment that annoys people, eventually hurts them, and turns them off of a service.