i am required to be there. otherwise i can't talk to teachers, arrange meetings for my kids and their friends, talk to my landlord, etc. sure, for some of these there are alternative ways, but usually they tell me if i want to be able to get a quick response (or a response at all) then i have to use their communication tool of choice.
for example my current landlord lives in a different country, that means i use his chat app or expensive international SMS or phonecalls, which would result in much more difficult communication.
teachers share photos from their activities only on whatsapp/wechat. they will reach me in other ways for important stuff, and in fact the directors of one school told me that they hate it too, but many parents are only reachable that way, so the parents force the school which would end up forcing me, at least if i want to get the photos and casual information, and not just communicate for emergencies. by insisting on a different way i would be the only one that everyone else has to make an exception for. and for many that means they would rather not bother.
also in many cases people do care about me but do not have the technical capacity to understand different communication tools. they barely can use wechat or whatsapp. and on top of that in china all good alternatives are blocked anyways. many matrix servers, for example. the only workable alternative would be deltachat because it works with email. but only if i get them to install the deltachat client, because most people read their regular emails only once a day or even less frequently.
in any group the choice is usually forced by the majority. and it would take a lot of energy to explain and convince everyone to change their preference. i do have more important things to worry about.