> My personal moral code is that lying is bad; this is an article of faith for me, a central tenet of my religion
To which I say it's a big simplification. Rules like this have all sorts of exceptions. If you say you never lie, it's highly likely you're lying or just have weak introspective skills.
In fact, I'd say it's instructive to go back through your examples and apply the parent's dogma. For example, if the dogma is heartfelt, then parent is going around signalling this trait to any potential love interest. That narrows the field, but it's narrowing it to those who find that trait desirable.
I'm not endorsing the dogma-- e.g., it filters out those who would find it desirable if only OP could break the ice first. But that's no reason to find it social unfeasible.
The classic test case is: what if the Nazis are at the door, asking whether you're harboring a Jewish refugee in your attic. I personally would lie in this case, and I believe most Quakers would as well.
A more subtle example: exaggerating the effects of climate change to motivate people to take action, for example claiming that Miami will be underwater in our lifetimes if we don't act. A lot of people I know do fudge the truth in this way, even if it isn't a conscious act of lying. I personally am not in favor, partly as a matter of faith, partly because I don't think it's an effective longer term strategy, but at the same time I think the argument for it is defensible.
BTW, a very good inquiry using that particular example is Dan Ariely's interview on Amanpour: https://www.youtube.com/watch?v=aLheBtBpZQw ; this example comes up at about 14:10. I can really recommend watching it, as Ariely is really trying to understand human behavior, not just retconning principles to justify his personal positions.
Both lies are used to gain political power by Politicians.
Both lies cause real harm. Saying the lie about Miami while simultaneously saying you can lie about it due to your faith is as wrong as the right saying there is no chance global warming is real.