It is not that the Left has different morals from the Right, it is that the whole notion of morals is anathema to the modernity of Leftist thought. The deluding of oneself that morality does not exist outside the reach of the state, fairly puts into context the ideology of Leftism. One can not support and promote ubiquitous government programs, and the use of those programs to advocate fairness, equality, and "a level playing field," and still be tethered by moral moorings. At least not the moral moorings of the Judeo/Christian tradition or even that of natural law and common sense.
It is morally bankrupt to believe that one solves issues of poverty by empowering government to make the wealthy less so in an effort to enrich the poor. For government can not create wealth but only confiscate it, and in so doing it mitigates that wealth's ability to promote economic growth and the creation of jobs. Even a million dollars placed into a savings account gives the bank who holds that money the ability to loan out 10 million dollars as a result of fractional banking. That same million dollars given to government has only about 100 thousand dollars impact on the economy because of the costs associated with bureaucracy.
It is morally bankrupt to advocate for same sex couples (and presumably any combination of humans who "love" each other) to marry. This position suggests there is no difference between the sexes, and therefore they are interchangeable in the millennia-old tradition of marriage, which is the bedrock of civilized society. There is no morality in the notion that men as fathers and women as mothers provide no specialty to raising children, and that that function can be performed just as aptly by any two adults.
It is morally bankrupt to allow, and even encourage infanticide because an unwanted pregnancy is an "inconvenience." It is especially morally bankrupt to turn a blind eye to the harvesting of organs from murdered fetuses to enrich an organization like Planned Parenthood. The barbarity of abortion, the killing of a unique human being, is practiced by the Left with reckless abandon, and even funded by taxpayer dollars, many of whom are opposed to this murderous practice. It is unfathomable in any civilized and moral society that such an inhumane and disgusting industry could be allowed to thrive.
It is morally bankrupt to encourage the weeds of government to flourish in the garden of Liberty, choking off the fruits of freedom. There can be no greater moral bankruptcy than to limit the opportunities of some to participate fully in the pursuit of their happiness in exchange for electoral support for those who are wholly responsible for such limitations. And the greatest moral bankruptcy expresses itself in the continued advocating of systems of government that have not only failed spectacularly, but have caused more death and misery than any religion, ideology, or ethos in the long history of man.