I agree completely, the clipboard is non-trusted. Yet the fact remains, how can we transmit an arbitrary string from a secure app like a password store, to another app in need of authorization? Lets build constructive conversations.

Ostensibly, yes. Because (as 'StavrosK said), if I don't then we can't even begin to talk about security on that machine yet. We have to start with assumptions somewhere.

If software on your machine is compromised, your machine is compromised (or will be in short order). You need to make reasonable concessions and stick with them in order to get anywhere.