Actually i do understand, critisism is something everyone needs from time to time. Also Frontier chose to listen to the community, that means they get both positive and negative comments.
I agree they did a great job so far, but that doesn't mean that there's no room for improvement, and i don't doubt Frontier woud agree with that.
To make things clear, the issue is not with the criticism and comments regarding possible improvements per se as that helps making the game what it is. It's the bashing of additions they have implemented in-game because some don't care for the new content. And you go on about DX12 mentioning it's not added as most don't use it AndyC did say the following:
As for DX12, we considered it back at the start of the project 2 years ago. Our conclusion was that while DX12 would certainly help by reducing draw call overhead, we've done many other DX11 tricks to reduce the overhead ourselves, and that there are still a significant number of people who are running Planet Coaster on Windows 7 / 8 / 8.1. While it is possible to target a game at both DX11 and DX12, we felt that this would give us the worst of both worlds - to efficiently use DX12 you need to really commit to it and change an awful lot of code, which given the timescale of Planet Coaster was a tough call
Ultimately they decided it just wasn't worth it to implement DX12 and doing so would have affected the game's development in other ways so can't really fault them for that.