So, what do you make of atheists who feel abortion is wrong?
You do realize that objections to abortion are not born solely of religious views, right?
The problems are often worse in those cases. Either way, in opposing free access to abortion a person is asserting an intrinsic moral worth to an undeveloped organism that trumps the freedom of a person to choose what they do with their own body. Given that the majority of abortions do not even actively destroy the organism makes the whole thing even more sinister, since they are asserting that the undeveloped organism has a right to nourish itself at the expense of the legally restricted individual.
Asserting intrinsic moral worth to anything is essentially a religious view, in the more general definition of religious. When the person just plucks the belief from thin air and starts asserting it, the possibility of convincing them otherwise may be much dire.