You are confusing "pure gold" and "solid gold".
He is.
"Pure" gold is 24-karat, it means that something is made out of 100% (or 99.99%) gold.
To be a complete pedant
"Solid" gold means that the item is made out of gold (even if it is an alloy) throughout and not just plated with gold on the outside.
Bingo!
... intended to drive readers into an anti-government rage, and thus generate clicks.
And boy does it work!
18-karat gold is not solid gold. A watch made out of 18-karat gold is not solid gold.
Well a it's solid 18 carat gold watch (at least the casing is). And reportedly it's more 'solid' than 24 carat (or even finer) gold.
It's later than you think, the joint Russian-American space mission has already begun.