Okay, so here is how I understand what happened in the first video:
Students were protesting, and that's okay, even with the Chancellor of the school. Then, just like Wall St. these protestors start to camp out. Now, unless it's a designated are, or has been allowed temporarily, setting up camp in public is illegal. The protestors at UC Davis were asked to leave for the night, and come back the next day, because they weren't allowed to camp over night. To me, that sounds like a fair enough request. The protestors decided that they weren't going to leave, so more security officers were called in to ensure that the protestors vacated the campus until the next day. The protestors decided to have a little sit in. If you have ever had a sit in, which I'm sure most of you haven't, it's hard to move 20 people linked together. That's a lot of weight. Okay, so the protestors won't move like they have been asked to, and the security officers decided that they have to move the protestors. Now One officer deals with the sit in, while the others deal with crowd control (that's why the other officers did nothing), so the about to be angered protestors don't get violent. Next; the spray comes out. Obviously they are going to use the spray rather than batons, and guns on non violent protestors. The amount of spray was used, is probably legal! Yes that's right! I said it! Now you can call me names, or think for a moment! Excessive force is when the officer uses more force than is necessary, or required to subdue, or hault whatever is going on. Did everyone fail to notice that even though a lot of mace was used, the students did not move? To me, that wasn't enough force to remove these protestors.
One more thing. Like I said before, there is two sides to every story. Other people hear realize that, why can't others?