Re: So all you businesses running Redmond software ...
It's pretty sad that the first reaction to feds doing stuff like this is that they're sneaking in and adding their own spyware. More of a condemnation of the feds to have let their reputation slip so far.
The saving grace is that they (allegedly) did this using the malware itself, not the holes in Exchange. If you weren't already being attacked by malware authors and had failed to remove the web shell yourself, they (allegedly) did nothing. Presumably people cynical about the feds would have already done this.