Why are cryptocurrency communities so tribal?

People new to the scene often discover that many cryptocurrency communities are very set in their beliefs, to the point of actively or aggressively excluding other coins or points of view even. The phenomenon is so prevalent it even has its own name, "(toxic) maximalism". This is because of:

1. Financial investment: Many people have a financial investment in their chosen coin succeeding.
2. Emotional investment: Many people have an emotional investment in their chosen coin succeeding (e.g. tensions between BCH and BTC camps after the Blocksize War, but there are plenty of examples).
3. All-or-nothing outcome: Cryptocurrency is a "winner take most" phenomenon. Cryptocurrency is an absolutely cut-throat free market, with no rules and lots of competition. Due to the network effect (a currency is better when more people trade it), the first coin to truly breakthrough to the mainstream in adoption will outstrip every other coin 100x in size. This means that every coin has to be playing to win, and if a coin's community is not planning to go to #1 then they're better off not bothering to try at all. Of course this produces a very "us against the world" mentality by default.

Bitcoin Cash is shooting to be the coin used everyday by the whole world, so it does have that mindset.

tip

This does NOT mean the BCH community should be unwelcoming, closed to innovations in other coins, hostile or exclusionary (a mistake made by some other communities). Individuals can allocate their own resources among any number of coins as they see fit. The vast majority of BCH adopters see it as natural for users to hold multiple coins if and where it makes sense for them, and for all projects to compete in the free market. However, the overall Bitcoin Cash community attitude will be along the lines of "We are going to make BCH so much better than every other coin, that eventually everyone in the world will want to trade it and rarely or never need any other cryptocurrencies."

Disputes with other Bitcoin forks

A notable exception is the heightened hostility the Bitcoin Cash community has towards the Bitcoin (BTC) and Bitcoin SV (BSV) communities, due to the acrimonious history. New entrants from either of those communities should be aware that the BCH community has its own very distinct opinionated philosophy and flavour. Community members will generally be willing to educate newcomers, but also quickly lose patience with any concern-trolling or disingenuous "debate" from typical BTC/BSV talking points without a sincere desire to see those assumptions from a new perspective.

See also: Should (or will) Bitcoin Cash rebrand?

See also: What is Bitcoin maximalism?