I know. But that's really where I, personally, make the decision to not care. Group chat with two dozen mates equals stupid banter, exchange of memes, lately some pictures of the young ones everyone seems to suddenly have, recaps of school day mischief. I don't say anything there I wouldn't say in a crowded room and neither does anyone else.
For something as deviously criminal as 'you got pot man?', the private chat function is alright.
Obviously the 'nothing to hide' fallacy is nonsense, but so is pretending every communication warrants the highest security parameters at our disposal.
Signal is a nice app, have it installed among pretty much every other messenger. But none of my friends, colleagues and coworkers use it. I have one contact out of almost a thousand on there. The desktop client only runs in a browser, Telegram can be open on all kinds of devices and synch up (ncTelegram on a VPS where pretty much all my communication is relayed, in my case)...
I know all the criticism, from the question of why they had to cook up their own crypto and nonfree server to the Russians behind it. It's still the best app I could sell to a lot of people who're not even close to tech literate.