You can say that about Apple users too, but the zealotry has somewhat declined as Apple products has become more mainstream.
Historically Linux users where people that actively choose to use Linux based on a combination of technical & philosophical reasons, thus they are more passionate about it.
Most common Windows users get Windows preinstalled from the store where they bought the computer. It is not really an active choice based on reason, therefore no reason to have a holy war.
The more Linux becomes mainstream, the holy wars will become more & more fringe. Systemd is pushing Linux more into the mainstream.
