It's very easy to excite the base with incendiary comments. We've seen throughout the campaign that if you're willing to say really outrageous things that are accusatory and attacking President Obama that you're going to jump up in the polls. You know, I'm not willing to light my hair on fire to try and get support. I am who I am.
Basically, he is saying "oh that Republican base, they are like animals. They are just too stupid to get me, they want someone to entertain them and show them something shiny. Well, I'm not stooping to their level." He seems to have the same view of Republicans as the mainstream media, who think conservative Republicans are a mass of unevolved cretins. That we don't like him purely because of his style. That just proves that he really doesn't understand conservative Republicans at all. We don't like Romney because we have absolutely zero faith that he will govern as a conservative. He has a terrible record in Massachusetts and has already said he wants to increase the minimum wage and tax the rich as President. It's also pretty clear that he won't repeal Obamacare, which is based on his own universal healthcare plan. Also, it seems weird that Romney is unwilling to really go after Obama given the merciless attacks he has leveled against his own fellow Republicans.
Which brings me to the real evidence that he thinks Republican voters are stupid. The actual content of his attacks on fellow Republicans are 100% hypocritical and anyone with any memory can see through them. Romney savaged Newt for supporting an individual mandate in the past, despite being the only Governor, Republican or Democrat, to actually pass an individual mandate in their state. Attacked Newt for his plan to combat illegal immigration while at the same time not being clear how his plan would actually be different. He even accused Newt of funding abortions despite the fact that Newt has a 98.6% lifetime rating from the National Right to Life Committee while Romney was pro-choice for years. Recently, he attacked Santorum for voting for earmarks that he himself received and voting for No Child Left Behind, which he himself supported!
He probably can't wait until the nomination fight is over so he can pivot to the left and never have to deal with the hated Republican base again.