I tend to just not invent "rules" out of thin air.
In absence of this supposed "rule", where "Something can not be immoral if it is the best of a series of bad options", you'd need to actually consider whether a decision is immoral. The rule shortcuts that and lets you say "well, there's no other option, so I must be in the clear morally here", which would be laughable if it wasn't so dangerous.
That's not a quote that appears anywhere prior to this in the thread, from what I can see. You seem to have made it up from scratch here.
The rule given above is "Something can not be immoral if it is the best of a series of bad options". In the context of the thread, it's being used to justify creating a fake persona and providing false details about yourself as part of a strategy of maintaining anonymity. And already the cracks start to show: the other option, "just don't respond" is classified as bad, and thus doesn't count as a viable option. So what you're left with is "lie about yourself", which the rule holds up as being definitely moral because it's the "best" option. But "just don't respond" is only described as bad because it doesn't give you maximum anonymity.
If I'm broke, and I need some money for lunch, "steal from my richest friend" could be reasonably argued to be the "best" of "bad options". I need to eat, it'll hurt them the least, so lets crack open their wallet. Because I get to arbitrate the option pool and the definition of "bad" and "best", I've got a neat package that lets me absolve myself of all tricky moral quandries.
I don’t think you can argue that steal from friend is the best in that situation. If truly the options are steal from friend or starve to death right now, then perhaps but that’s not realistic.
I’m not sure what you think someone should do rather than make the best decision given all options.
There are many ways to absolve yourself of tricky moral quandaries. But I don’t think using a fake name on a web form is a mora quandary.
If we’re in a world where the only options are that one can’t lie about themself online or not participate then that’s a bad world.
I think it depends on the intent of the lie in that lying to get out of advertising seems ok, but lying to trick someone into a date seems bad.
Of course it’s hard to truly know, so people have to fall back do what they think is best and rely on the guidance of trusted friends.
This is how morality in general works, I think. And we just have societal morals that are widely accepted. I think advertising is immoral and unethical, but that’s not a belief commonly held by enough to make it into culture and laws.
In absence of this supposed "rule", where "Something can not be immoral if it is the best of a series of bad options", you'd need to actually consider whether a decision is immoral. The rule shortcuts that and lets you say "well, there's no other option, so I must be in the clear morally here", which would be laughable if it wasn't so dangerous.