This smells of a case where they are looking to broaden their reach through precedence.

What are you even talking about? I’ve never heard of such thing as “warrant precedence.” There’s case law precedence, and a ruling on a case can create precedence that impacts the legality of warrants. If anything, they’re actively trying to prevent such legal precedent by not informing their targets, who would have been the best suited to file suit against them.

It’s not overblown, they are modifying people’s systems without their knowledge or consent

I’m about as upset about this as I was about the guy who hacked into people’s routers to close known, commonly exploited vulnerabilities. Which is to say, not at all.

Why are you upset about this? Do you think those people were harmed in some way by the FBI’s actions?

Having botnet malware on your computer harms you. It also harms other people - everyone who is impacted by the person controlling the botnet. It means your private files are likely visible to criminals who have no qualms about exploiting them for personal gain.

Removing the malware, therefore, helps you.

This is like walking into a stranger’s house uninvited through their unlocked front door, removing the extension power cord + ethernet cable that their neighbor had plugged into their outlet and peripheral, and then leaving. (Side note - in many jurisdictions, walking into a house uninvited through an unlocked or open door isn’t a crime.)

Whether their intent was good or not is irrelevant.

Nonsense.

Their intent was good. The end result was good. Their means were not excessive, given their goal.

Could they have used this exercise as an excuse to hurt someone? Sure. Did they? Did the tool they were using malfunction and brick a nice old lady's home desktop PC? Did someone get charged with a crime because of evidence collected outside the scope of the warrant of this case? Not as far as we know or have any reason to believe.

That doesn’t mean they didn’t, but you fix that with oversight, not by refusing to allow the government to combat botnets.

And if you’re concerned about the FBI breaking into your computer through the use of one of these vulnerabilities, then secure your computer. It’s irresponsible not to.