javascript – Why Facebook pages are so heavy?

When I open the simple links of Facebook, my browser downloads many files. Some are js files, relatively large. Once I downloaded 30 MB when opening a page that I manage. The following image shows a simple publication of Facebook, which downloaded 10.9 MB locally. Why is it happening? Why Facebook is heavier than any other website? Every time I open it, I have to wait a long time (my internet is a bit slow). I am using Chromium Version 57.0.2987.98 Built in 8.7, running on Debian 8.8 32 bit
enter the description of the image here