Imagine I make a laser bug zapper and install them at every fast food joint in the US. 9999 out of 10000 times it zaps an insect. 1 out of 10000 times the laser fires it blinds a child.
I could wax all I want want about the 99.99% accuracy, the _relative_ accuracy won't mean a thing to the million people blinded by it.
When there is a mix of spambot garbage and human beings that being harmed the right metric isn't the ratio. Blinding a million children wouldn't go from unacceptable to acceptable just because the level of insects swarming around a restaurant increased by a factor of 10. The harm stands alone, and there is a level of harm which could not be justified by any amount of boring spambot influx.
I care about the crime rate, or car accident rate, or botched surgery rate, because it tells me the odds that something bad will happen to me.
Given a stable rate of bad things, population growth alone causes more bad things to happen.
If we took your argument about absolute harm seriously, then we should, say, encourage population reduction until there are only 10k human beings on the planet. That would surely minimize the number of bad things that continue happening to people.
It is trivial to ban every spammer: ban everyone.
If you ban most spam while significantly harming some of your users, you've done your job poorly.
I don't really see how this line of argument really translates to this issue with Google. First of all I should have acknowledged that imprisoning data is almost assuredly unacceptable and that unless Google is acting directly in response to a law enforcement action they should give you a way to download your data when they tell you that they have chosen not to continue the business relationship they have with you.
But there will be cases where they cannot do that, and in some cases it will be a mistake but the reason they cannot solve this problem cheaply is because usually it is not a mistake and so litigating 99,999 cases to find the one worthy of saving is a hard case to make, why should Google pay for that?
I should have mentioned up-front that this article scared the hell out of me and I'm probably moving to Fastmail. I've had my own domain for going on two decades and am still grandfathered into the free gsuite for it but I'd much rather pay someone who will support me than use a free service that could cost me access to data that I might want again in the future. I also realized I could be vulnerable to a trap where my DNS account is disabled at the same time my email is, meaning I couldn't even move the DNS without first recovering access to my mailbox.
I don't think it's that big a leap to say that it is unlikely that there is any plausible reduction in spam from an automated facility that justifies the kind of extreme harm and disruption created by locking an honest user out of their decades long email-- which might be more damaging to them then a home fire--, with zero effectual recourse. Yet it happens because the cost of the spam is on google's 'balance sheet' while the damage to the user is not.
So that is the sort of argument that I'm making. I think google is creating damages wildly out of proportion to any plausible benefit, but it works out for them currently because the damages are externalities.
Were Google a more conventional company the threat of litigation (even litigation they'd ultimately win) would help internalize some of these costs, but Google has grown to such a size and scope that even the federal government finds prosecuting them to be extremely daunting.
There should still be a solution though. Maybe this is a terrible idea, but one idea: Google could sell a service where you pay them $200 and they thoroughly review your case, tell you what happened and work with you to restore access to data, maybe even setup email forwarding for 90 days or something that comes reasonably close to making you whole even if they can't restore service.
If in the course of doing this work they figure out they screwed up closing the account in the first place, the money is refunded. Of course fraudsters would not generally want to sign-up and pay this money as - even if the information of how they were caught was worth $200 - that would create a paper-trail. And it could still be the case that Google is under a FISA letter or something and can't fulfill this service, and in that case they'd refund your money as well.
Not about how you detected them, but you should tell them what you detected. E.g. if you're using a spam filter, you don't want spammers to know which exact keywords triggered the classification, but it wouldn't hurt much to let people know that their account was locked for sending spam instead of some other reason.