Kind of a brain dump on the MC/Laura thing--not with 0.12 complete yet, but it looks like we're heading for a repeat of previous behaviors:
I've been disappointed in Laura for a while. I'd expected, given her age, life experience, and what MC had to say about her toward the beginning, that she'd be the other adult in the room--someone MC could depend on for ideas and for help, if not truly a partner then at least a second-in-command. That's how she sees herself, that's how Kallie sees her, and that's even (to a degree) the way MC sees her. But it just isn't the case. OK, I won't blame her, exactly, for her mental breakdown, but it still happened. She's shown herself to be impulsive. It seems to come from a good place--she isn't malicious--but it's often ill-considered, and often results in her putting others at additional, and unnecessary, risk.
Meanwhile, MC is pretty much the same MC as in N&T. Caring, protective, self-sacrificing, all of which are good qualities--he's a genuinely good man, which is a big part of what gets him the ladies. But as is often the case, positive traits become negatives when carried too far, and that's where MC is (in both games)--he's far too self-sacrificing for his own good. And he insists on being so, even when they rightly explain that if he works himself to death, he isn't helping them. Ten out of ten for putting your people first, but minus several million for clear thinking. He persists in this course of action after Kallie calls him out for it, resolving, not to stop, but to better hide it from her. So, for Laura/Kallie/Shelley (or any combination of them) to believe they have to go behind MC's back for his own good doesn't seem too out-of-place.
So, you have two stubborn characters, both of whom doing their best to do what's best for the group as a whole, who often don't agree on what's best for the group as a whole. And it's pretty common for each of them to have pretty bad ideas in this regard. But apparently neither of them is able to actually talk through the disagreements and reach a resolution, so they both instead just do whatever they feel like doing. Unsurprisingly, this often leads to bad outcomes.
So, why the "hate" (or anger, or frustration, or disappointment, or whatever) for Laura? I see two big reasons: (1) Laura's ideas are more bad, more often, than MC's; and (2) since we play as MC, we identify with MC--others' faults are always worse than our own.