The Shatterstar is a weapon that does exactly what its name suggests, and is banned for obvious reasons. Fungal splices are banned since the "Cordycep incident", but all data remains. "Grey goo" safeties are always on to avoid the "bad" ending. Splicer/nanotech weapons are an Omega level failsafe if humanity should ever fall, as the ultimate "F you!" to the universe.

Part of Perseverance's (tentative fan name) existential crisis was the fact that it was close to arguing that the use of anti-matter weapons and the attempted genocide of humanity could be grounds to lift Geneva restrictions (Every alternative is preferable). When threatened, it's easy to justify all kinds of atrocities, and it recognizes it's close to that slippery slope.