1) Do you think there's any merit to the notion that abortion is a destroyer of love and peace -- let alone the greatest?
I take it you mean voluntary abortion. No, I do not agree. Teresa was either unaware or neglectful of the very serious consequences of unwanted births. There are few things that destroy love and peace any more fiercely than having to put up with a being whose very existence one resents - or being that person rejected.
2) Is there any truth to Teresa's statement that abortion teaches people to use "any violence to get what they want"?
Probably not, although I don't doubt she means it. The often unspoken premise that often comes with such statements is that people will learn to deal with adversity if they are just put through enough suffering to "mold their character".
In a nutshell, Terese does not care about the hardships and nocive effects of an unwanted birth, and that makes her judgment callous and jaundiced. I suspect she developed a mean, even cruel streak.
For some people it is too much of a temptation to point fingers and tell people that they ought to feel ashamed for not behaving better, circunstances and limitations be darned.