Ugh, okay Meredith, let's pretend it's impossible to handle this with user experience that makes the user acknowledge their conversation with a WhatsApp user is not secure. Meanwhile if the only viable way for this conversion to occur is to have WhatsApp on both ends, the situation less secure.

It is a privacy concern, not a security one.

So according to Meredith, the choice is between less overall security or not having conversations with people who don't use Signal.

Could you cite this please? Because I do not see this beeing said or implied.

That could makes sense for her salary but it surely is a net negative for Signal users some of which will have to install WhatsApp since they won't be able to afford not to have those conversations.

Entirley different conversation, accusations and projections. So dropping this.