The purpose of the GNU system is to give users the freedom that proprietary software takes away from its users. Proprietary operating systems (like other proprietary programs) are an injustice, and we aim for a world in which they do not exist.
To improve the use of proprietary systems is a misguided goal. Our aim, rather, is to eliminate them. We include support for some proprietary systems in GNU Emacs in the hope that running Emacs on them will give users a taste of freedom and thus lead them to free themselves.
引用自 GNU Emacs download - GNU Project
GNU Emacs 对非自由操作系统上支持的态度就是这样。
抖动的原因之前有讨论，就是在于把 Carbon 更新成了 NS。倒不是故意引入bug，只是为了支持GNU NS 这个Objective-C开发环境项目。目前的办法就是回到Carbon，但是官方肯定不会这样做，只能等新的窗口系统有所进展。