One was the organized extermination of a specific ethnic people, the other is the wanton, indiscriminate destruction of national youth. The Holocaust was the product of centuries of anti-semitism, paranoia, resentment, and ill-fated opportunity; abortion is the logical outgrowth of a flippant, crass, myopic culture. The Final Solution was a xenophobic, racist program of concentrated destruction; the eruption of American abortion reflects a wanton, out of control consumer culture taken to its grotesque final extreme.
As a matter of history and fact, there's simply no way to compare the two. People do so because the Nazis represent ultimate evil. But it's a misleading and inaccurate comparison. That's all.
I think those are good descriptions for the most part but they don't negate the commonalities. Of course, the motives for each genocide will have some differences but they will also have some things in common. Fundamentally, we are still talking about the systematic destruction / murder of certain types of innocent people. Both of these people groups are innocent and targeted for extermination by people who advocate killing certain innocent human beings. That being said, of course there will be obvious and valid comparisons that can be made between the two people groups and the two groups that would target these innocent people for death.
The most obvious commonality is that they are all innocent humans who have been murdered in mass numbers. Anther common theme is that there are facilities where the mass murder is carried out. In America we call them Planned Parenthood abortion mills and in Germany we call them death camps. In both cases, to knowingly help build the facility, you have made yourself as guilty as the guy slitting a throat or the guy ripping off an arm and crushing the skull.
