You’re right. Romney has refused to commit to reversing Obama’s anti-deportation policy. But, in fairness to Romney, it must be understood that his plan is to impose a more liberal, more comprehensive immigration policy which would render Obama’s recent move irrelevant.
Romney is aiming for total amnesty.
In order to understand Romney’s liberal immigration attitude, it should be remembered that his father, George Romney, was born in Mexico. His family had helped found a commune so that they could practice what they called “plural marriage” (polygamy) in a socialist setting. Anti-communist attitudes in Mexico forced the Romneys and their wives to flee their Mexican commune and sneak into the United States in the early part of the twentieth century.