While Republican voters might appear to be for immigration reform by the polls, their idea of reform is vastly different than what these people are proposing.
They first want a secure border... meaning no flood of new illegals, drugs, gangs, etc.
They clearly feel lied to by democrats saying the border is the most secure ever. Just look at the 50,000 children who have just crossed since January. If you can't stop children, how do you plan on stopping the "bad guys"?
Republicans would also support more work visas -- both skilled and unskilled. They don't care about having more immigrants here. They want an orderly process which no administration has been able to provide.
Obama's blanket amnesty isn't too popular but most Republicans would be up for the debate if they were confident the problem wouldn't keep compounding itself with new illegals.