Such hate. I haven't developed for windows in years but I have read with interest all the stuff about .NET core and things - all moving in a good direction, seems positive.
To say that .NET is a shit copy of Java is a bit harsh..
Saying everything should be developed natively is far too optimistic in this day when everyone wants the same app on their PC (windows), their laptop (mac), their phone (android) and their TV (WebOS or whatever). No company wants to develop the same app in different ways many times and support them all individually. Attempts at cross platform frameworks are not perfect by any means, but they're better than the alternative.