Why oh why do people throw non-default templating languages into their tutorials when it's not relevant to the tutorial at all? When you write your views in ER

Why oh why do people throw non-default templating languages into their tutorials when it's not relevant to the tutorial at all? When you write your views in ERB, your tutorial's accessible to everyone who's used Rails, and the HAML / Slim / Mustache / Liquid / whatever people can convert them over easily. When you write your views with something other than ERB, someone who's only familiar with ERB has a much harder task, especially if they're new to Rails and don't know much about alternate templating languages.