Do you feel the same way about homosexual marriage or polygamy?
Absolutely not!
A homosexual or polygamous marriage in one state would become an issue if the people moved to a different state. This would clearly become an issue in terms of the "full faith and credit" clause in Article IV of the Constitution.
As much as I would wish for every state to ban abortion, a woman would be allowed to travel to a state which allows abortion. The abortion would occur in one state and the other state's laws would not apply. In simpler terms, some states allow the sale and use of fireworks while others don't, there is no prohibition from someone travelling to a different state and using fireworks there.