Yes, you (and I, let's not forget that we kinda agree that this is bad design) might not want to share your private phone number just to contact someone via Signal. But I feel you're painting this a bit too black or white.
If lives are at stake or not, Signal might or might not be the right solution. If people feel that their life is at risk, I hope they know how to evaluate the trade-offs - or have someone around that can explain it.
We both don't like Signal. I don't agree that it should be dismissed and emotional appeals are ~questionable~, can probably be turned around (see first paragraph). Individual decisions need to be made and if Signal is a good fit or not for a specific scenario isn't an good indicator about the general fitness of Signal in general imo.