Why are some "Conservatives" so Hostile towards Obama?

I was reading the comments on cnn.com (yes, old habits die hard) as well as Facebook following the Massachusetts senate race, and I was honestly saddened and sometimes alarmed by the level of venom/toxicity some people were expressing towards president Obama. 

I wonder if any sociologists are studying this because to me it is bizarre and a little scary.  I don't know what to make of it, but I'd really like to understand it.

I decided to brainstorm possibilities:

* Could it be racism - are people exploding with emotion because they are subconsciously racists and must come up with anything they can think of nasty to say about him (save the "N" word). 

* Could these (I assume) conservative people have snapped because they feel so powerless given the liberals ha(d) a super majority and the ability to pass anything they want if they had a mind to (which, apparently they don't have a mind to)

* Could they be acting out so extremely because an administration is in power that believes almost the polar opposite of what they do?

I'd like to have a conversation with some of these people to find out what is motivating their ugliness, but I feel it would be impossible to get them to simmer down enough to allow themselves to really get to the heart of their anger - or be able to express themselves without the raw emotion getting in the way of communication.

or am I just over-reacting....... maybe I'm seeing hostility and hatred where there is none.

Thoughts?