I realize the title is an over-generalization, and liberals are all for holding class enemies and other political opponents personally responsible for their actions. But when it comes to all sorts of groups liberals cater to or apologize for, looking at personal responsibility as the cause of their actions or situations is way down on the list. When it comes to the poor, ethnic minorities, non-Christian religious minorities, criminals, and even terrorist enemies of America, there is always some excuse for their bad situations or behavior that doesn't involve their own actions and decisions. Terrorists aren't attacking America because they are murderous savages twisted by their odious religious beliefs. Oh no, they've become terrorists because they lack economic opportunity in their own countries, and they are attacking America in response to evil American policies. In other words it's our fault.
Criminals aren't just bad people who choose to take things that don't belong to them, injure and kill others, and commit all sorts of other offenses -- unless they are affluent white criminals of course. They come from disadvantaged parts of society, therefore there are all kinds of excuses as to why they had to turn to crime.
Poor people aren't poor because they make bad decisions. Of course not. They're poor because they are oppressed by the privileged classes and the "system." If you are well-off, the fact that other people aren't is your fault. It's your fault and the fault of everyone who hasn't voted to have the government seize more of your money and redistribute it through programs to help the poor. Even suggesting that many poor people might be primarily responsible for their own condition is just heartless and mean. It's also pretty amusing that to many liberals, suggesting that poor people are poor because they made bad decisions is seen as an insult akin to calling the poor stupid. Yet at the same time liberals apparently think the poor are too stupid to do things that are necessary to help themselves out of poverty, or at least to alleviate their conditions. That's why they need government intervention. We certainly can't expect them to take the responsibility for doing things necessary to help themselves.
I've always found the distinction between the right (and libertarian) emphasis on personal responsibility, and the left's cult of victimization to be one of the sharpest dividing lines on the political spectrum. This divide separates the sides on various societal topics, and even crosses into foreign policy in the case of the blame America first crowd.