We needed a good standard setup that fit our needs. People can opt to use something else as long as their code meets the style guidelines. But its easier to use the same tool. We share tips and tricks a lot. That way we improve our workflow as a whole.

Why not vim itself? We tried it. They are more used to GUI centric editors. (shrugs)

As long as it is implemented as a reference standard and not enforced, I think it is a good idea. The official tools are built into the standard PC build that new starters get, and inexperienced new starts would be expected to use it as company documentation will be optimised for the "company standard" tools. Experienced workers should be free to use what-ever they like as long as their output is 100% compatible with the company standard (so doesn't pose any collaboration difficulties).

I never got this either especially when editorconfig exists.

I can understand it, if it's not too draconian. It's nice for some central power to have coherent walktnroughs on how to set up an editor to lint, etc. If another dev wants to use a different editor and can make it work, it's fine by me, but I can't see anyone "supporting" every editor out there.