Here, you forgot this: /s
They (McCain and Grahamnesty) are pro-amnesty neo-cons.
WOT/defense/pre-emption is their major issue and they want amnesty to generate more volunteers to the army for boots on the ground, as did GWB.
These are their MAIN issues(principles), not taxes and spending (McCain voted against the Bush tax cuts) or even deficits although they may be down on their list.
So Hagel turned into their worst opponent. And they took a meaningless petty looking symbolic stand against him that they never planned on holding to. This is how they fight battles they think are important(they gave Kerry no opposition)
Hagel is not at the top of my list of peeves, but he is their's.