I find it difficult to understand why some people get angry with babyat babies' crying.

"Get angry at [noun]"
Talking about any baby so it's plural, and you're talking about their crying so it's possessive (add apostrophe)

The other day, I saw an old man who iwas angry at a crying baby and her parents on the train.

"Was" not "is" because it happened in the past
"A" before crying baby because it's one baby that isn't specific

I think babyies' crying is healing for people.

Not a grammar mistake, but I think it would be better to say that it can be healing instead of is healing, because you talk about how people can also dislike it

I find it difficult to understand why some people get angry withjust for the reason of a baby crying.

The other day, I saw an old man who is angry at crying baby andwith her parents on the train.

I think baby's crying is healing forthe people.

I find it difficult to understand why some people get angry withhen a baby is crying.

The other day, I saw an old man who is angry at a crying baby and her parents on the train.

I think when a baby cryingies it is healing for the people.

I find it difficult to understand why some people get angry with babyies crying.

or, with a crying baby

The other day, I saw an old man who isgot angry at a crying baby and her parents on the train.

or, I saw a man get angry at ....

I think baby crying isbabies are healing for people.