I guess they don't want to give people more ideas that they don't need Time Warner to have CBS. Time Warner pays them $XXXX per year so if people got used to just watching on CBS.com then Time Warner might not feel the urge to get them back. CBS also makes most of their money from TV ads, not internet so they might be losing out on tons of revenue that way too.
All in all, CBS is doing what it can do to get what it wants. They want more money and they are gonna try getting it one way or another. I understand costs go up sometimes (which still blows my mind, stuff should be getting cheaper, not more expensive! ) but when is it enough?