Yes. But then we invented science and "common knowledge" was proven ignorant time and time again.
>It's like asking for a source to prove the sky is blue or that the earth is round...
Hardly. I can't look out my window and see what the temperature was thousands of years ago.
>This community claims to be one of educated professionals
You're claiming that, not 'the community.'
What is intellectually lazy is not providing information that verifies your claims, and instead preferring to debate the social circumstances of an internet discussion. You're not obligated to provide a source. You don't have to do it. But don't think you're somehow more intellectually honest or hardworking because you refuse to.
If 2 seconds of googling solves this problem, then you should have probably just done that rather than arguing about whether you should need to.