Can someone educate me why someone is proposing such laws in the first place? What's the motive? What are they going to gain by bringing the proposed changes?
Because they have been bought and paid for by the existing ISP monopolies, who stand to gain enormously from the loss of net neutrality, at little to no extra effort on their part.
I see lot of downsides to that like for example in long run ISPs might end up offering their connection for free as Google/FB etc. are already providing their own ISP services (may be they started so because of this law!) => every large corporation move into ISP business offering their service for free instead of paying someone else!