Sure, it could be. Might not though.
We're all gamblers when it comes to the truth, and you have to be holding some cards to be taken seriously most of the games worth playing.
Could is not a strong card. It really doesn't mean much when it comes to promoting a strong or extreme position without a high probability of harm or benefit attached to it. It's the start of an argument, not an argument of itself.
"Oh it could be... the aliens plotting to invade could be in his garage... sure it could happen that you win the lottery."
'Possibly' is like 'could' - almost directly interchangeable in fact:
"Oh it's possible... the aliens plotting to invade are possibly in his garage... sure it's possible that you win the lottery."
But, probably not.
Possibility alone is not an argument. Almost anything could possibly mess someone up, almost anything could possibly set a murderer off for instance. Have your read some mass murderers' messages? There's stuff in there like the women exercising at the gym made them realise how they'd never get anyone to love them and then they got snubbed by a woman and went mental.
So, possibly my going swimming will make someone kill someone, best not go swimming any more then!
Of course, you probable wouldn't suggest that women stop swimming because it might set some random nutjob off. Because the pleasure that many women take in swimming is taken to far outweigh a small probability of it doing so. Our rights trump the probability of their madness, people shouldn't have to live in fear that they're going to be someone's excuse. But, if the probability of madness was high - if men almost always went insane when women were swimming, if they were just physiologically unable to control themselves; well, I suspect that it wouldn't be the case that our right trumped their madness because the probability of harm would be so much higher.
Merely noting that something is possible is a potential beginning; somewhere to go and look up statistics and start measuring harms from if it seems probable enough to you on the basis of your prior and the actions you'd take on the basis of it being true or false to be worth looking into. If someone tells you there's an alien in their garrage the next step, if you think it probable enough to be worth looking into, is to go, 'Well, let's have a look then.' Not to start planning your response to the invasion fleet.
What the probability is matters. We can all imagine things possibly happening that are not implausible, yet in reality are not at all probable. And because our brains are not operating on floating point variables, we don't actually have a way to feel how small the probabilities behind various degrees of possible are. So, going with your feelings of shock about 'how could something possibly' is a bad call. To say something meaningful, in the sense that it ought to guide policy and action you have to use maths and numbers, not feelings. You have to use data, not instinct. You have to be able to promote an idea of how probable it is, not just note that it's possible.
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While we're here I suppose I should note that 'Just look at life before porn... it wasn't awful.' Is not evidence for porn being bad either. It's, at best, just an argument for it not being an all surpassing good - and even there you haven't controlled for socioeconomic factors so you can't really be said to be comparing like for like. Methodologically it's not sound.
And even ignoring all that, the argument still falls down. Maybe there were some healthy relationships before porn, but the days before porn included....
Oh, you mean the days when young girls were sold off to be fucked when they had their first period?
Or perhaps you're talking about the golden era of traditional gender roles, when it was legal to rape your wife and some women were essentially prisoners in their own homes.
Or perhaps you're going more traditional, Aesop's fables:
'A woman, a spaniel and a walnut tree, The more they're beaten the better they'll be.'
Even disregarding the methodological flaws, noted above, life before porn was not good for some people. Of course there probably were some healthy relationships back then, and maybe even the majority of such relationships were healthy. Or maybe not. As I'm sure you'll agree, the numbers matter in determining quite how horrifying history is.
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Aside:
Personally, I find the unequal treatment of women in the workplace and government in history to make even the definition of healthy relationships in historical terms very difficult. Were I to define a healthy relationship it would go something like 'An equal, fair, and mutually beneficial relationship that makes those involved happy....' But how can it be equal and fair when one side has the majority of the power? We, or at least women at various points in time, were deprived of access to significant power, and thus of significant agency, from a very early age.
Imagine telling someone that the most they could aspire to was to be some man's secretary and the only way they could hope to interact with most of society was through their husband. I've no doubt you could grow to largely ignore that, if you grew up with it, but then again people grow up to largely ignore being blind too. I'm unsure under that interpretation how you'd even begin to define a healthy relationship as distinct from Stockholm Syndrome.
I wouldn't be able to take that. I wouldn't want to live in that world and I'd be constantly timid and afraid of even someone I'd otherwise love if they wielded that sort of power over me.
Which isn't to say that all historical relationships were examples of such patterns. I'm just saying that even the act of definition there is going to be very difficult. You can't really talk about healthy relationships without reference to the psychology of those involved, and that also involves references to the surrounding power structures - which will vary both with time and place. You can't meaningfully abstract over large portions of history without putting in significant work to normalise your terms across contexts.