The only answer I can give here is that there is a limited amount of volunteers who are both knowledgeable enough to write software with the complexity as a program like KiCad and are willing to invest their own time in doing so. Donations on the KiCad project are growing, but it it is by far not enough to hire a team of developers.
And KiCad is making big progress. Just a few years ago it was mandatory to hack into KiCad’s files because of bugs or missing features. These day’s it’s rarely needed, and it’s more an “extra option” to do very unusual things.
In KiCad, graphic polygons on copper are also used for “net ties”, which add the ability to connect different nets at a specific place on the PCB (For example Feedback tracks from shunt resistors, or star ground points).
Learning KiCad’s limits and workarounds (such as using extra pads for this) is (still) part of KiCad. Every EDA program has it’s own quircks.
Also, I almost forgot:
In KiCad V5 you can combine graphic shapes and a pad into a “complex pad”. To do this, select both the pad and the polygon, and then select “Create pad from selected shapes” from the popup menu under the right mouse button. If I do this with the Antenna footprint from my earlier posts, then DRC does recognize it. This antenna footprint was probably made before that function was implemented in KiCad.
In KiCad-nightly V5.99 there is a new and better way to make custom pads, but that does not mean that sites like Snapeda will start using it soon. You’re always responsible for the footprints you make and/or use in your project, and checking them carefully is part of the process of PCB design.
The via thing is no biggie, I would not have bitten into that at all if Piotr had not responded.