Sure, that's advised in interviews, where you're about to make a decision on someone's livelihood, hence the importance of reducing bias. That's a completely different context than in casual conversation at a social event.

This is nonsense as there is no such thing as unbiased personal interaction.

It's a networking event, not an interview loop.

In the same lines, don't ask anything. Everything is a bias. ie, What do they do? - Also a bias as they are engineer, or product, or sales, or whatever.

In most parts of the world this is not true.

Even in the US it's ridiculous advice, driven by fear rather than a rational assessment of policy. Asking people where they are from is just fine.