Ignoring the red flag the company would require whatsapp, I can easily see a company not forcing you to use it and being okay.

But as op mentioned

> kids' sports activities and parent groups

Try telling your kids football team coach that you object to Whatsapp and your kids friends' parents that you will not join Facebook for privacy reasons, it's a much harder ask, they might say fine, but you can't expect other people to change their behavior based on your beliefs. No matter how right you are.