The outrage over "poisoning a child" is ridiculous
Coming off a season in which Walt had Jesse murder Gale to save their lives - a sweet, innocent guy who wouldn't hurt a fly (he cooks meth but he believes in personal freedoms to choose and I guarantee if the character were real, he would own anyone who tried to take him on in that argument) - the "shockingly horrible" thing he does is...make a kid temporarily sick with some berries in order to prevent Gus from murdering his freak'n family.
People say "poison a child" and leave out the context to make it sound like something completely different...as though he murdered a child.
The way people talk about it, Walt may as well have just used the damn ricin and killed him. Would've saved him a whole lot of trouble with the lie to Jesse. Instead, he deliberately used the berries to make sure the kid survived.
And this was to save his freak'n family's lives. I mean, I'd shoot a kid dead to save my family's lives. I don't give a damn about *someone else* in that situation. That person can blow me.
But no, Walt isn't even allowed to make Brock sick for a few days to keep Gus from murdering his kids. Because poor Brock, the CHILD. He's turned into Heisenbergggggg....eeeeeevillll.
This is the fault of Gilligan, though. Horrid writing, underscored by the fact that they never showed how Walt got the berries from his yard into Brock's stomach. That would have been the most interesting part of the episode, but they skipped it because they either couldn't figure out a good way to explain it, or they stupidly thought the "shock" of seeing it was Walt at the end (not a shock to anyone who isn't extremely gullible/unaware of television tropes) was more important.