I am confused, that doesn't seem to be true. In FireFox for Android, I can select and copy both the address of the page that I'm on[0] and any particular link on the page[1], both by doing a long tap on the link/URL I wish to copy.

[0] - http://i.xwl.me/2017-10-26%2010.57.48.png

[1] - http://i.xwl.me/2017-10-26%2011.01.24.png