You could also ask about whether they think it's private. And if they say yes, ask them what it means. Does it mean only sender and intended recipients can read the message, or is it fine if the service has someone check the content. Would they agree on the notion "it's OK my nudes I send to my SO are up for grabs for anyone who hacks Telegram's servers", or do they think should Telegram plug this gaping hole.
Also, people tend to state they have nothing to hide, when they feel they have nothing to fight with. But I can't count the number of times I've seen a stranger next to me on a bus cover their chat the second I sit next to them. Me, a complete random person with no interest in their life is a threat to them.
You may try sitting near a completely open-space developer and watch what they are doing, and see the 10x performance drop on average, while there was zero privacy on screen at all times. It helps to realize that people not always behave logically (we have lots of group instincts legacy) and it doesn’t always work as a proper argument.
So they take theatrics over logical evaluation of the situation. Cool. Tell them Durov could have locked himself out of their data and spared himself the trip to behind bars.
Durov is in jail because he is not doing moderation of public chat channels, as far as has been shared. It has exactly nothing to do with encryption or privacy, in both directions (that is, it doesn't in the slightest prove that Telegram doesn't share private data with various states; and E2EE of private chats would not have done one iota to keep him out of jail).
You probably don't use Telegram channels much. There are some drug and prostitution related channels you can search for but they disappear rather quickly or are totally empty.
Christo Grozev shared screenshots of a few CSAM channels yesterday, but if you search for them, they do not seem to exist.
Telegram clearly does less pre-moderation than Facebook, but they are smaller and have less computing and they do not seem to rely on the masses of Nigerian moderators that work for 5$/day as Facebook does.
Also, people tend to state they have nothing to hide, when they feel they have nothing to fight with. But I can't count the number of times I've seen a stranger next to me on a bus cover their chat the second I sit next to them. Me, a complete random person with no interest in their life is a threat to them.