You've got it backwards. At least on FR, the vast majority of the anti-immigrant posters are people who disliked Bush first and then use immigration as an excuse to attack him.
Reminds me of the Old Media saying that Bush is responsible for partisanship when in fact it's the Democrats that are opposing everything Bush proposes.
Remember, the Bush team has not taken the field yet on this issue. As soon as they do, the anti-immigrants will fold faster than Saddam's army, because the anti-immigrant propaganda is based on Buchanan/Tancredo lies, distortions and racist slogans.
If what you say is true, then according to the last FR poll on the matter 68% FR members & lurkers dislike Bush anyway.
One day it will occur to you that this isn't about Bush.