That may sound farfetched, but Comcast is "regulated" by the Obama-controlled Federal Communications Commission. As you may know, there has been some concern among people in broadcasting about the possibility of O's FCC abusing its authority by shutting down outlets as political retaliation against perceived "enemies." I think that might her point, although I'm not sure.
So, if anything, Land should be biased against Obama, not in favor of him.
In any event, stock ownership doesn't disqualify a judge from any case unless the company whose stock he owns is a party or has a direct financial interest in the outcome.
Finally, if you think a judge's stock ownership disqualifies him, the law is that you have to say so before the judge rules on your case. Otherwise you can go into the hearing and say, "if I win I won't say anything but if I lose I'll say the judge is biased." Courts don't stand for that kind of gamesmanship.