It should be illegal, period. That's why I think not participating in political voting is a valid option as well for a Catholic.
I agree with you. Abortion should be illegal and your line of reason here is legitimate. As far as I understand the authorities on moral theology, not participating was a valid option under these circuмstance. Voting for Trum was also a valid option, if done for the right reasons.
We should save our condemnation for Catholics who voted for hαɾɾιs. Not that I expect anyone here to have actually done that.