[Spoiler] I don't understand why everyone is pissed at Barry for what he did at the end of season 2 and at the beginning of season 3.

First of all, apologies about the confusing title, I'm not really sure what I can and cannot say in the title because of the spoiler thing. Anyway, correct me if I'm wrong, but when Barry went back in time and saved his mother, he created another timeline called Flashpoint where they live but then he goes back in time to reverse it but things have changed.

Assuming timeline 1 is at the end of season 2 before he goes back in time, that would make flashpoint timeline 2 and post-flashpoint timeline 3. Now I say that because there are massive differences between post-flashpoint and pre-flashpoint. For example, the conversation between Iris and Barry on the porch never happens, Julian has been in Central City for a year now, they know and hate each other, etc. But Timeline 3 is not Timeline 1. It is a parallel timeline with different things happening. So when Barry says that he erased baby Sara, Diggle in timeline 3 didn't really lose a daughter because he never had one. Diggle in timeline 1 has a daughter. Barry does not remember anything in Timeline 3 because he is not the Barry of timeline 3, the one who spent a year working with Julian, the one who refused to go back in time to save Dante, the one who knows about the feud between Iris and Joe. He is Barry from timeline 1, the one who likes to put his dick in the timeline.

So Diggle and Lyla being kind of pissed that Barry erased their daughter from existence is kind of dumb because they never had a daughter. It's a bit like if Wells from Earth-250, which is extremely similar to Earth-1 bar some minor changes here and there, would come to Earth-1, become friends with Team Flash then say something like: "Oh btw, on my earth, you guys have another friend and I accidentally killed him, my bad." then the whole of team flash would be devastated by that news and shun wells-250. That would make no sense.

Or maybe i'm getting everything wrong.