You know, when I was more into the fandom, I saw Eremika shippers talk about how they'd be an actual couple that loves each other, while these people complaining only see Historia as just a means to pump out kids, especially when they though humanity was dying out.
I wonder if people understand why AOT became so popular to begin with (and I feel that most of the popularity was the "killing Titans and trying to survive in a hellscape"). As for marriage and editors, Have these people ever tried creating a story before? I'm pretty sure one of the first things you end up realizing is that you need a good editor to help your story and possibly filter out shit, even if the relationship isn't always great. Alternatively, are people that pissed off over what happened that they can't comprehend that some things were always the plan, the issues HAVE to be from interference?
As for the romance....welcome to shonen, where the target demo really doesn't give a shit about it and all that you get is scenes that could be seen as "baiting" when it could be just the way characters are written in the story are always together because reasons.