I kind of see it too, but "I don't feel like going to the gym right now" resulting in being locked out of all her content going forward? It's no so much that it's crazy as that (1) it isn't very obvious, and (2) the "penalty" seems a little excessive.So I kind of see where that's coming from.
And even more broadly than that, "don't be a dick to the LIs" is insufficient advice to keep you on the LI's paths, because some of the things that will kick you off a path don't at all constitute "being a dick." For another example, not inviting Annie to join you and Luna in the horror server loses Annie's path. That isn't being a dick to Annie,* especially since you know how easily-scared she is. But if she isn't in that server, she doesn't get scared, she doesn't come to MC's bed, etc. Or not asking Luna about her gloves after that server. Or not hiring the delinquents to torch the yoga teacher's car.
Bottom line, if you aren't using a walkthrough, you're probably going to lose some of the LIs' paths without meaning to. Lots of the things that'll drop you are pretty obvious, but some aren't.
*Yeah, you could argue it is, since she wants to join you. But it's at least arguable.