If my local barber tells me "don't come back here ever again", I'll find another barber within 15min walk from my place.
If Facebook bans me, I might lose a way to communicate with hundreds of people, I might lose access to managing my business and talk to my clients. And often there might be very few viable alternatives.
As Facebook and other large companies become dominant in certain areas, their responsibility should grow, too. And banning users based on some algorithmic detection, without the ability to contact human customer support to understand and fix the situation, should not be acceptable.
We can keep saying "uninstall WhatsApp/Messenger/WeChat!" but for a lot of people this it not viable, because it means cutting social connections or losing clients. There are countries like Spain where WhatsApp is the way to communicate on-line and few people use other IMs.
There are a few things that can change it - either a technology shift (e.g. mobile revolution ended Windows dominance), black swan event (like pandemic that moved everyone to hybrid/remote work), or government regulation. If we don't want the government to intervene, we need to accept that we might be randomly banned by an algorithm and there's nothing we can do about it.
There are alternatives. If we don't want Facebook in general to monopolize every aspect of our lives, we need to actively refuse being assimilated by the Borg and prioritize these alternatives.
Ok, your small online store is banned from advertising on Facebook and Instagram. What will you do?
Do you mean advertising or keeping an internet presence? If you mean "internet presence", I'd would use one of the numerous site builders and I would create a pixelfed and mastodon instances to publish content.
If you mean advertising: I'd write a post here about how my account was banned without justification...
You just need to stop contributing to it if you believe that it is harmful to you and you are okay with the consequences of your choices.
I am not walking around with a soapbox telling everyone they should leave FB and Instagram. Instead, I am simply not participating in it and hoping that this can serve as an example for others.
Meta can afford meeting regulatory requirements imposed by nation states.