You convince them in the same way you'd convince them of anything they're unsure of or against.
Give them a reason that they care enough about and make it painless enough and they may follow. Listen to their concerns and try to find ways to address them or to find workable compromises. Remember that you are placing an additional imposition on them. Asking them to switch services for you is asking them a favour. Each person (or social group) has their own motivations, perspective and other attributes which means that the tactic to win over each person (/group) should be different.
I'd caution against a hardline stance, I've lost friends (acquaintances?) who went down that path to what I'd consider a paranoid extent (going sms or email or "obscure" services only). It just became too hard to keep them in the loop when organising eg group events, so they started to get excluded. Their behavior just didn't make sense considering their (presumably low) threat profile, and they'd made the barriers to contact too high in comparison to the social value they brought.
In my case, these people were socially inept (selfish?) and felt that how we communicated was solely their choice, which is kind of true in a way, but the other person has the choice of whether they continue to try to engage.
I'm not saying that you need to entirely embrace these services as a necessary evil, but it's not a binary choice either. You can be easier to reach on the services that you want to use, and only rarely catch up on whatsapp from a sandbox machine. You can encourage people and help set them up on the services that you want to use. You can advocate for privacy awareness within the groups you're in. You can refuse to share more secret things like passwords on the less privacy-aware networks. All of these things will contribute to avoiding less privacy-oriented services.
Give them a reason that they care enough about and make it painless enough and they may follow. Listen to their concerns and try to find ways to address them or to find workable compromises. Remember that you are placing an additional imposition on them. Asking them to switch services for you is asking them a favour. Each person (or social group) has their own motivations, perspective and other attributes which means that the tactic to win over each person (/group) should be different.
I'd caution against a hardline stance, I've lost friends (acquaintances?) who went down that path to what I'd consider a paranoid extent (going sms or email or "obscure" services only). It just became too hard to keep them in the loop when organising eg group events, so they started to get excluded. Their behavior just didn't make sense considering their (presumably low) threat profile, and they'd made the barriers to contact too high in comparison to the social value they brought.
In my case, these people were socially inept (selfish?) and felt that how we communicated was solely their choice, which is kind of true in a way, but the other person has the choice of whether they continue to try to engage.
I'm not saying that you need to entirely embrace these services as a necessary evil, but it's not a binary choice either. You can be easier to reach on the services that you want to use, and only rarely catch up on whatsapp from a sandbox machine. You can encourage people and help set them up on the services that you want to use. You can advocate for privacy awareness within the groups you're in. You can refuse to share more secret things like passwords on the less privacy-aware networks. All of these things will contribute to avoiding less privacy-oriented services.
It's a transition, and a social process.