Soda is not in contact with your teeth for long enough to cause any damage, the acidity in basically all fruit would be just as bad by any meaningful measure of harm.
Carbohydrate snacks like crisps etc are much worse.
People eat fruit fairly quickly. But, many people sip soda for hours a day which is a vary different situation. Not only do they get acid but the constant low levels of sugar promote significant bacterial growth.
Also, unlike fruit soda has water and sugar, but no nutrients what so ever.
Carbohydrate snacks like crisps etc are much worse.