IMO "Reputed and trustworthy citations from scientific sources required, please." is just a more elegant way of calling bullshit

It's an elegant way of covering noise with more noise.

It is required. Just claiming something is well-known to counter someone’s suggestion without providing any evidence isn’t very productive.

No other suggestion was offered in the post I am referring to, just a "sources pl0x" ask. Here is the simplest counter example I can think of.

"Gravity is real."

"Reputed and trustworthy citations from scientific sources required, please."

You can get less and less ridiculous from here ad nauseam, but the point is made.

"It is well known" is a weasel word, and hence requires more substantiation when asked. If one has to rely on Googling on these matters, one can find so many contradictory views. So I wanted to know what reputed sources the GP was relying on to use "It is well known" for that claim.