Bad analogy. If insurance wouldn’t pay for birth control but would pay for a vasectomy then she might have a better argument.
The reasons why insurance companies are interested in paying for either vasectomies or abortions is that they represent stop-losses.
From an actuarial standpoint, its in their financial interest to cover them.
To the extent that abortions are not covered, it is because it is essentially licensed infanticide and brings a fresh set of financial risks that are not necessarily medical.