The problem relies in the website design and removing other needed fonts (the same will happen in other OS's if all fonts are removed), not only in the Simsun font removal, the IME components are needed for asian typing (IME stands for Input Method Editor = Text Input Processor).[WINDOWS 10] (maybe for Windows 7 too)
Support for reading asiatic characters in web browsers:
Due a problem I had ( HERE ), I found that in order to be able to read asiatic characters in asiatic webpages ( eg. www.qq.com ) using Firefox or Chrome, you must keep the SimSun text font, because it seem this is the default font these webbrowsers will use, and if the font is not found, you will not see asiatic characters.
In the attached image you can see the components that I kept in order to solve the problem. The IME components were unnecessary and they occupy much size, so I just removed them.
When a website design lists fonts to be used, it uses the first font listed, when the first font isn't found in the system, the next listed font is used, when the listed fonts aren't found, you will see rectangles (i have seen the rectangles at the right of 'Speakers' and programs names in the windows mixer audio when removing 3 fonts, reported today dec 5-6).Inspecting elements shows me these fonts being used;
sans-serif, SimSun, "Arial Narrow", HELVETICA.