"""Do you have proof it's "to save money"? or, as I suspect, you are just speculating.
They said all the other manufacturers do the same thing, and they have done it for so long that people have forgotten why exactly.
This is clearly not a cost cutting method. For all we know there is only one part that does the job and everyone uses it."""
You ask me for proof if using 600V spec part in 1000V circuit is to "save money?"That is common sense! Higher spec parts cost significantly more,all companies use cheapest parts possible to maximize profit. 99% of the time there is under spec part used anywhere,be it electronics,or mechanical maschines,constructing house or anywhere really,it is to spend less money.
What proof you have that its not to save money? I dont claim it is to save money,I do claim thats much more likely than opposite and there is no proof that it isnt to save money. Proof that could be easily made if they revelead the part.
"""They are likely trying to stop people like you from going ape over a single spec sheet figure that may not be relevant without a ton of other engineering test and historical data that would likely be difficult to comprehend to Joe Average."""
I cant believe you are blaming general public for being too inexperienced to deserve answer.Average Joe doesnt buy 1200 dollar multimeter.I think the idea that engineering community on average is too inexperienced and hysterical as warranty to hide important facts about use of underspec part is not right.
I am noob,I admit it,but I dont go ape for irrational reasons when I discover some product uses under spec parts in it.For example Rigol uses under spec ADCs in their scopes,I didnt go "ooo!!! Rigol uses under spec ADCs ooOH my god WORST T&M MANUFACTURER EVER NEVER GOING TO BUY FROM THEM AGAIN OOOOOOO!",I was more like "k lol".Using underspec parts alone doesnt concern me at all,hiding the part despite many people wanting to know what it was,that raises all kinds of red flags for me.
And yes yes,Keysight doesnt care about what I think,but I am not alone who is curious what part it is.