Two degrees is not a typo. The ships armors generally was designed to stop a very specific threat (your current assessment of main enemy current gun or next gun). The armor is hugely heavy, so you don't protect against shot coming from outside expect range. The armor rapidly tapperred. And there are reason that even if weight was less of an issue, you limit armor. Going from 1" to 2" steel in the weather deck makes a BB more vulnerable to AP fire from other BB by changing the angle of the shell to closer to 90 degrees. And all this feeds into the concept of invulnerability zones in WW2 for BB.
I'm aware of the concept of the invulnerability zone, thanks. But as far as I can tell, your "two degrees" figure is completely arbitrary. You seem to be saying something like "If this weapon hit at an angle that was two degrees off the angle at which it would have penetrated, then a two degree change in attack angle would often defeat the armour." Which is completely true, and fundamentally meaningless.
Going back to your original post, you referred to a rocket with in "level flight", which is a pretty good approximation to the flight of a heavy shell, and will lead to the rocket hitting, if it hits armour, the thickest part of the belt. You refer to tapered armour, but this is normally present below the waterline, where it will not be hit by a rocket in the horizontal flight that you describe! If it doesn't hit armour then, yes, it will have the ability to mission-kill by destroying sensors etc - but this is an ability that gunfire already has!
So really, what is the point? In a 1930-1940s environment, you end up with a weapon system that has no range advantage over cruiser or heavier gunfire and involves you placing a limited number of maintenance-intensive flammable, explosive missiles in positions vulnerable to damage by enemy action or the weather.
Calling people naive does not further discussion.
Navies make decision to fund or not fund technologies all the time. Often promising ideas are not funding. The interwar years saw very tough naval budget (almost nothing for Germany). It was merely a choice.
I explained why I thought that your attitude was naive, and I will try to do so again, more clearly. The existence and direction of funding is not "merely a choice", it is a product of internal and external economic and political factors. For example, the US did not "merely choose" to develop the technology required to send men to the moon, it did so because it was involved in a technological and ideological conflict with the USSR.
If you want Germany to develop ship-launched guided missiles, then you need an environment that not only makes that a good idea, but also excludes otherwise superior ideas - such as mounting them on aircraft instead! For an early-mid C20 Germany, this would seem to involve a naval threat being greater than a land threat, hostility with the UK, economic strength and no defeat in WW1, no air bases along the Dutch/Belgian/French coast. That appears to describe a shorter WW1 with a German victory in the east and status quo bellum ante in the west territorially, but not militarily. Now, that's a plausible enough outcome - no unrestricted submarine warfare would be a good starting point - but the point is that it requires a pretty huge change in the geopolitical environment. It's quite clearly not "merely a choice"!
Get the environment right and the funding will follow naturally. Otherwise, you're just handwaving the funding into reality.
