Your argument rocks, but something seems to be eroding it...
I'm assuming a typo, but this made me chuckle anyway; sediment is an inventive insult.
That said, it seems there is not much know-how about RTGs at ESA, which is most likely also influenced by political reasons.
So the ESA would have traded the (very small, but not zero) risk of radioactive contamination from a launch failure for not enough additional research gain.
It's called a "law", but it's just a joke observation someone made. And it's not that enlightening in the first place.
Fascism was one of the most important events and currents of the 20th century. And it's full of analogies to draw and historical lessons.
If we can't draw historical analogies from the most important historical event of modern history, where should we draw them from? Ancient Rome? The Falklands war? The 1900 Paris World Expo?
[1] The fine print: I don't know if there are actual preserved recordings from his research that bore any scientific value.
Sure, but that's either during to his clumsiness in experiments, or because of our refusal to accept such horrendous material for further use (even if they are scientifically valid otherwise).
That is, not due to some inherent logical or methodological impossibility of combining science with cruelty. If anything, not caring about the consequences (to people, animals, the environment, etc) can even accelerate scientific study.
That's why I brought it as an example.
To main it the point that we need to draw some lines through external normative systems (religion, morals, ethical concerns etc), because science itself is just a method of inquiry, nothing inherent in it about being humane or responsible.
From my understanding, this shortage is caused by the lack of nuclear power facilities in the USA - which supports the GGP's point about negative political/public reactions to anything nuclear.
The problem is that turning nuclear reactors into Pu238 requires a lot of extra work and equipment. They produce small amounts, but separating it out is tough. You can make more by irradiating other waste products, but that's not easy either. Apparently some stuff used for making nuclear weapons can be used for this purpose (note that nuclear weapons use Pu239, not 238) and the shortage happened because those facilities were closed.
But actively seperating out the required materials is the same processing step as is required for building nuclear weapons, and that's something that's a political problem, and will cost you a lot of money to prove and inspect everything every few days to ensure it's only used for civil uses.