How can there not seem to be a kind of consensus around this?

There were tons of citations, why does a simple idea written down need to cite work from 20 years ago?

The threshold of tolerance here is basically ridiculous, authors will be more predisposed to research and citations than to actual thinking.

I suggest if someone feels left out, they can make a claim and the paper can be 'amended or not' and that's that.

How on earth is someone supposed to have an 'idea' without a team of grad students ...