When animal images are used in general for folks, that isn't necessarily dehumanization as such but imagery/metaphor/parody. There is a difference.
The guy at Mulligans (note: a White bar that produced a t-shirt with Curious George the monkey with the caption "Obama 2008" on it) can say all he wants that he just thinks cute little Curious George and Obama look a lot alike...but he knows that blacks are taking offense and he doesn't care. I can tell from the way he's responded in the news and the fact he's gearing up to make more of these T-shirts, last I heard, after selling out of them...depsite the rancor this is raising.
From the PHNN ("Parallel Hood News Network") news archives we have the audio of a conflict between a little White boy and a little Black boy in which they were lobbing verbal assaults at each other after a third party had accused both of them of talking about each other's mama.
Black Kid: "Timmy you are a little punk. I told you that you stink every day because you don't wash. And when you do wash you jump into the toilet bowl after someone just took a crap."
White Kid: "Oh yeah, Jimmy? Well you are a little punk too. Your teeth are yellow because you don't brush them and instead you borrow your big sisters highlighter and paint your teeth florescent yellow"
Black Kid: "Well, well. You are so dumb that when our teacher asked you the question 'If Johnny had 3 apples and then ate 2 of them how many would he have left?' and you told her 'None because my momma always cuts up 3 apples for me in the morning and I eat all of them up".
White Kid: "That's nothing. You are so dumb that when the bus driver ask you 'Where do you live so I can take you home.' You told him - 'With my momma and my daddy.' "
Black Kid: Dunce!
White Kid: Weirdo!
Black Kid: Skunk!!
White Kid: Opossum!!
Black Kid: Orangutan!
White Kid: Monkey!!
Black Kid: "You called me a MONKEY! You are a racist! Don't you know how offensive it is to associate monkey images to Black people? "
White Kid: "Well you called me an Orangutan! Isn't that a monkey as well? We saw this during the field trip that we took to the zoo last month.
Black Kid: " The key difference is that when you are older and you call a Black person a monkey, being a White person it will be seen as your attempt to perpetuate the White Supremacist antics of your ancestors who were the oppressors of Black people.."
White Kid: "So when I hear you call me the same thing I should not be offended as well? I thought that you were my equal?"
Black Kid: "No. You shouldn't take me seriously when I call you names. This is just my anger at 400 years of oppression. Despite the fact that I was born in 1999 this pain is encultrated in me using ambiguous rules and double standards such as this particular one regarding the use of monkey references."
White Kid: "But didn't we learn in our science class that there is no genetic differences between any human beings, regardless of their race? We are all this way due to mating decisions over thousands of years".
Black Kid: "All of this science is true. But again I told you - you have to factor in two important things when this situation comes up - Black people have a large part of our self-sensibilities placed so much in the hands of what White folks do to them so you must be respectful of this fact.....and the fact that YOU ARE LIKELY TO GET YOUR ASS KICKED if you say it to them to their face".
White Kid: "Well since you put it that way - You are a Jackass instead."
Black Kid: "Jackass? - Well that's better"
White Kid: "Enough of this. Let's go pull the hair of Suzy. She's a real bitch when she yells at us".
Black Kid: "OK, let's go after that hoe".