Riker didn't "abort" the two clones.
The clones had clearly not reached maturity. They were still growing in the cloning tubes. If they were "done"/alive, they'd be wandering around the colony, not being incubated in those cloning tubes. I submit that the term "abort" could certainly be used here to describe, as near an approximation to what we can conceive, regarding Riker's actions. It certainly wasn't murder.
Riker took out his phaser, aimed it at two innocent life forms, helpless to defend themselves from Riker's up-coming attack, and Riker killed them both.
1) Riker and Pulaski.
2) The clones were not alive.
3) Riker did not kill them.
Your question doubleohfive has no connection to the event in the episode.
You still have not answered the question. I refute your dismissal of my question, too. Riker and Pulaski were violated. Is it exactly the same thing as rape? No. Nor is the "mind rape" shown in season five's "Violations" or in Star Trek Nemesis. But in all three instances, the characters were brutally assaulted and violated against their will.
Again I pose my question: Would you consider it murder if a woman aborted a baby she became pregnant with after being raped?