>As for it was a good idea, this has already been debated and acted upon, there is no need to repeat exactly the same arguments.
Well, the same debates happened over many other decisions debated, acted upon, and later regretted and reverted. At some point the GIL seemed like a good decision too!
The GIL is a good decision and has been a sound engineering tradeoff for decades. It's only been the past few years that running the interpreter without a GIL has been even remotely feasible (cf the gilectomy project). The GIL is a relatively straightforward way to hold back a tremendous amount of complexity.
Similarly, TOML writing is a ton of completely. The org isn't opposed to adding toml writing to the stdlib fundamentally, they just aren't rushing and want to hammer out all of the grossness first.
Obviously the complexity level is different, but to me you sound like someone complaining about Linux adding support for a new filesystem, but read-only at first. Why all the hostility?
As for it was a good idea, this has already been debated and acted upon, there is no need to repeat exactly the same arguments.
You will find the detailed rational in the PEP, and link to the various discussions.