[vetinari]

No, it does not shut down discussion, it shuts down bikeshedding. There's a large peanut gallery with strong opinions how they would do it, but because they never did something similar, they have no idea what they are talking about and what trade-offs are involved.

Unsurprisingly, people who know these things, for example because they develop it, may disagree with the peanut gallery and do it in a way they consider the best.

[saagarjha]

I would much rather hear a reason why something wouldn’t work than the responses saying “ok, how would you do it” and “ok, well someone would have done that if it was legitimate but they didn’t”.

[vetinari]

It's not that simple; explaining one reason why something would not work means re-examing many of the underlying assumptions and not many like to go deeper than that one problem at hand in isolation. The "ok, how would you do it" forces thinking about underlying issues, because the solution you propose has to account for factors you otherwise wouldn't think of.

It is not a new problem either; this video is 9 years old already: https://www.youtube.com/watch?v=ZTdUmlGxVo0. It is almost one hour long, but well worth to watch to see the two different approaches to clash.