I’ve changed my profile photo to a photo of Signal next to its logo along with a short message asking people to contact me on that medium. That way Facebook gets dirty data (an incorrect profile photo). I recon that people pay more attention to profile photos than status messages too.
Then to win whatever argument they fire at me I reply with something like “Thanks for your insight Dave but I’m not asking you to quit WhatsApp. I’m just asking you to use Signal for our group chat and to keep in touch with me. You are welcome to use WhatsApp to keep in touch with others. I’ve done my research, I know what they are doing at a technical level and have decided to stop using WhatsApp.” A statement like this opens up very few avenues for argument because you are not directly accusing the other person of being ignorant. So they will not usually feel the need to defend themselves. You are merely informing them of your preference. They may feel the need to remind you of their argument and the best way to reply to that is to paraphrase their argument accurately even if you don’t agree with it. I know it’s mean and manipulative but arguing about privacy is just a waste of time IMO. Some people get it, some just don’t. Leave it be.
Then to win whatever argument they fire at me I reply with something like “Thanks for your insight Dave but I’m not asking you to quit WhatsApp. I’m just asking you to use Signal for our group chat and to keep in touch with me. You are welcome to use WhatsApp to keep in touch with others. I’ve done my research, I know what they are doing at a technical level and have decided to stop using WhatsApp.” A statement like this opens up very few avenues for argument because you are not directly accusing the other person of being ignorant. So they will not usually feel the need to defend themselves. You are merely informing them of your preference. They may feel the need to remind you of their argument and the best way to reply to that is to paraphrase their argument accurately even if you don’t agree with it. I know it’s mean and manipulative but arguing about privacy is just a waste of time IMO. Some people get it, some just don’t. Leave it be.