If we are being serious they are both in a toxic relationship as one mentally abuses while the other physically abuses. Luckily this is manga where everyone can just laugh it off.
Yeah he is rather toxic too. But I disagree on this being something we can laugh off instead of frown off, as it is trying to portray this as something "cutesy" when put altogether.
And every time Wily E Coyote's rockets blew up it would shower the desert with bloody giblets. People who can't separate fiction from reality are severely mentally ill and need to be institutionalized until they learn to stop trying to ruin things for normal people.
I don't remember his rockets having that effect~.
But, you do realize there is a huge difference in joking about something humorous - such as gore and death - versus trying to downplay/trivialize/acceptify a serious issue such as domestic abuse, by treating it as some kind of comedic relief, right? The fact that you (or whoever it was you referred to with "people") can't differentiate reality from fiction should not matter regarding this, as this is true in both cases.
ps: and this is not even that normal kind of DA we have been desensitized with, where some 'tsundere' hits an mc when she gets embarrassed but they are fine the next second, implying that the violence was all fictional even in-universe (or more commonly put, operating under comic-book rules). In this manga we have seen that she literally already knocked him out cold (for quite a while at that) once, and she is still persisting in doing this. Though even if this was not the case, it would have been a bit too, with the way this is portrayed (not merely expressing embarrassment, but something she does routinely - presented as a 'cute' trait).