Maximalists are, of course, the hardcore fundamentalists of crypto true believers that the one and only true
coin is Bitcoin and that all other projects are by definition shitcoins.
It is not Bitcoin Maximalists, but the aim of creating new cryptos is to fix some of the Bitcoin problems by childishness solutions. This solution (new coins) deserves to be called shitcoins.
Many cryptocurrencies (99%) have taken easy solutions to bitcoin's problems, so it's no shame to be described as shits, at least technically.
hardcore fundamentalists of crypto are those who call some currencies with real changes (ETH, Monero,..etc) as shitcoins,