Matrix was never on switching.social's list of Whatsapp alternatives, because I feel it is too complicated.
It is however listed as an alternative to Slack.
I know people will disagree with my decisions, that's why I released the site under a libre CC-By-SA licence so that people can modify and reuse the material on their own sites if they wish.
The foreign language forks have already diverged in their own directions and that's fine: