I haven’t found ostracism for using channels outside of Facebook. I have plenty of friends and acquaintances that I keep in touch with via Snapchat, email, and text.
Its very similar to not being a blue bubble in some regards, but Facebook has a much broader scope than just being a messenger platform.
Excited for the EU to fix the closed messenger issue, then I can have 3rd party clients to bridge all my communications securely into one unified view, just gotta make sure that these large companies don't try and open up these platforms by hiding your end to end encryption keys on their servers :D