I try to have compassion for her, but she says things that I just find hard to find any compassion for.

Here's an example of what happened the last time she was here; bit of background first.
MIL's sister A had a baby at 19 that she gave up for adoption. Her strict, religious family sent her away to have the baby to avoid the disgrace. A stayed away after baby and very quickly ie 6 months after birth got married to a man the family didn't know on the quiet.

Now we were talking and I was told that A might lose her job soon, as her contract was not up for renewal. I said "oh that's terrible, are you worried about A?" MIL says "no, A has had plenty of opportunities over the years to save money" with a sour tone as if A had made her bed, she can lie in it sort of way. I said, "that's a bit cold, isn't it?" which I probably shouldn't, but it just sounded so danm cold the way she said it! MIL starts with "Well, I'd never see her out on the street, but you know, she really upset the family with all that baby stuff and getting married...blah blah" and goes into some more of the background that does not, let me tell you, show MIL in a good light!!

Remeber that all of this happened 40 years ago!! And A is still the naughty girl who got pregnant!

I think she shouldn't have been gossiping about A, she didn't pick up on any of my verbal or body cues that the subject was making me annoyed and I would prefer that she drop it.

My compassion is for A, but what do you think?