At least that is how I understand the statement.
It did not say "we have no idea, but it's probably not security related".
It said "we are still investigating, but it's probably not security related".
Those are very different statements.
The first, yeah, reasonable complaint.
The second could mean a lot of things. Usually, in these situations, people want to be able to put numbers on things, etc.
So it could reasonably mean "A something like "a bunch of machines are falling over in a datacenter with out of memory, we've determined why, it was an internal bug, fixed it, but are still gathering data about how much was affected, etc, before we say more"
Or whatever. IE saying "we are investigating" doesn't necessarily mean they are investigating the root cause, they could be investigating how long it will take to fix it, ....