There is no such thing as "Bitcoin Maximalism".
People who use that expression are usually just looking for a sorry excuse why their beloved Altcoin fails.
So-called "Bitcoin Maximalists" are usually simply conservative in that they prefer a decentralized, stable, well-developed blockchain as the basis for a digital currency over some random, premined or ICOed copycat with feature-bloat.
The term
Bitcoin-maximalist was first coined by the developer of Ethereum, Vitalik Buterin.
Maximalist believes that Bitcoin
BTC is the only cryptocurrency that matters.
Maximalists believe that most altcoins do not have real use cases and speculatively trade on exchanges to get more BitcoinsBTC.This is a philosophy that has the right to exist.