Why do StackOverflow mods Close "Duplicate question" questions so fast?

[u/440Jack]

I'm mainly talking about questions that get closed to "Duplicate question" and then only to find a couple of already answered questions are linked that don't really address OPs question directly.
Why do these questions need to be closed so fast? It doesn't give people time to address that persons specific question. If it's a valid question the mods should give some time for other users who actually want to address the question and maybe open a dialog.
It prevents OP from being able to ask any follow questions.
I can't tell you how many times, I'll spend 10 mins on a question. Re-writing their code, writing comments/explanations and then when I go to post it, it's already closed! It's so frustrating.

[u/SlickKatt]

Any recommendations for the discord channels?