Ordinals is not a "Bitcoin protocol" it is a centralized and separate thing and the only link it has to bitcoin is that it is spamming the chain with arbitrary data. It is also not exactly inscribing satoshis, it is just injecting an arbitrary data into the chain which is an abuse of the Bitcoin protocol and its blockchain.
Ordinals and Prunes are not built by Bitcoin protocol but they indeed are parasites on Bitcoin blockchain which is a biggest. strongest and most successful blockchain in cryptocurrency space.
They parasite on Bitcoin blockchain because they know that it has biggest user base and most of capital in cryptocurrency market condenses in Bitcoin ecosystem. Developers of Ordinals and Prunes know that if they can deploy their token projects on Bitcoin blockchain successfully, they can attract massive capital to their scam projects and steal bitcoin from naive Bitcoin owners.