Firstly, if you don't like Facebook, don't use it. I know I don't.
Secondly, you can still find alternative views on the internet if you look. I know I looked prior to the referendum. Unfortunately, relatively speaking, I found little evidence of reasoned argument from the Leave camp. Events after the referendum, such as their lack of a plan and leadership, confirms that was probably an accurate reflection of their position rather than any "bias" of the internet.