Many abolitionist wanted to end slavery by legal means through religious and political pressure

Hm, not sure what is meant here. It's not options as both legal means and religious and political pressure are true - abolitionists wanted to end slavery and they used many means.

But legal means and political pressure opposed other means, such as violent conflict (such as between the south and north), so maybe some sort of general description such as "non-violently" or "peacefully" would work?

Because so many people use them and say that they are good

Is this form a story we need more information