[stillbourne]

Science operates on a system of checks and balances, not a free speech model. If your paper can't pass peer review then your paper is what is clinically referred to as bullshit. Now there are people who bypass the system of checks and balances by publishing on pay to play journals but scientist came up with a solution to that too, Impact Factor. They took all the journals and rated them by how much of the content that they publish has an high impact on science and how much of it is bullshit. If you can't get your paper to publish in a journal with an impact factor higher than say 3.5 then you're probably bullshit.

[nebulousthree]

Checks and balances are a perpetual game of cat and mouse. While yes, they do raise the barrier of entry, it doesn't account for nepotism or favouritism, which would be the equivalent of lifting the ribbon to let someone through. It can go so far as to make legitimate attempts at entry unreasonably difficult or downright impossible, making the paper publish only papers pushed through a rigged system that appears on the surface to be of value. It is only through time or by investigation that it is found that a paper reputation is increasingly fraudulent.

[stillbourne]

Yes, and we even have a system for that. Retraction. https://retractionwatch.com/

I'm not saying the system is perfect but it works over time.