That prioritization (by the RCC) also has long been hard for me to understand. Putting “wearing a rubber” in the same category as pushing lethal drugs or abortions?
I’m not disparaging that the RCC genuinely reads God’s word that way. I just ... wow.
In the same way, directly sterilizing someone (deliberate destruction of source of life) is objectively worse than other kinds of maiming (say, deliberately breaking somebody's nose).
Notice the word "objectively." As in any sin, subjective guilt can be either aggravated (by defiance or malice, say) or mitigated (by faulty knowledge or lack on full willfulness.)
Perhaps somebody else could recommend a good work on morality which would deal with this more systematically and comprehensively. All I can think of is Right and Reason by Austin Fagothey, which I am delighted to find is available in its 2000 Edition.
Enjoy.