This is FUD, and a lot of people are trying to use this against Core. Any developer has the right to create a proposal. Don't you remember that Pieter Wuille proposed that we increase the supply to 42million (after the first 21 million have been mined)? This does not mean that the proposal will be implemented. IRC sipa said that they would not merge this.
Crazy things are proposed all the time-- and there is nothing wrong with that, it's part of how understanding is advanced.
Though in this case, Pieter proposed no such thing. Bitcoin's creator did: The original 21 million limit didn't work right and after a few hundred years would have repeated the coin distribution all over again, and we fixed it. The april-1stness of BIP42 was just the the silly way this trivial soft-fork fix to Bitcoin's consensus rules was described.