Yes,she's a child,or at least a young teen(like 11-15),and she was trapped in a doll's system for god knows how many years, forced to essentially watch a massacre and mass slaughter,trapped into a box for again(god knows how long)and basically was manipulated and lied to by someone who she thought was her close friend,lost her father ,etc.

Like she's not some "manipulative snake" or whatever Harley said about her.
She's a traumatized and hurt child who is trying to stop a monster who organized a mass murder.

Not even trying to sound like a huge stan but wow.

"Oh she's a bit annoying".
Ok,kids are gonna be a little annoying and sarcastic and snarky.
They're kids/teens.

"She left Kissy"
She's a barely 2 foot doll who isn't close to being built the same as the bigger bodies or mini huggies and he's also the source and cause of all her trauma and she was already low emotionally due to what happened to Doey.
Yeah,her running away was a bit screwed up but literally what could she have done?
She would've been killed,so would we have,had we tried to fight him.

Her running away was probably the smartest option.

"Oh she blamed us for killing Doey" ,techinally we did kill him(even if it was in self defense),and it's not like she was there when she saw what happened or what went down.
All she knows is that her friend is dead techianlly due to us.

Hell, the only time she techinally "betrayed us" was when she derailed the tain and even then,that was techinally her saving our life cause the Prototype would've killed us.

I also feel like,imo,it's way too late for her to be suddenly a twist evil villain when her goals and character has been made pretty clear. 

"Oh but Harley Sawyer said-"
I'm gonna be so honest..you guys are trusting and believing the words of a psychotic,empty lunatic who dissects and kills children for a living.
Plus this dude is a prime manipulator,so why are we taking his words for fact?

I dunno how hot of a take this is but I feel like a lot of the Fandom either downplays or tends to ignore how Poppy is a insanely traumatized child.