But laws are just encodes morality.
It was illegal to harbour escaped slaves. Or hide Jews from the Gestapo.
Laws have nothing to do with morality. Or justice.
But they all reflect the morality of society to a degree, whether the democratic majority, or the powerful minority.
The question of "are laws there to enforce morality, or enforce public order?" is the key one. And, I think, very easily settled by looking at the laws we choose to implement. Almost none of them enforce moral behaviour (e.g. you must give 10% of your income to charity), they're all about enforcing how we interact and how we're ruled.
Yes, of course. Morality is relative. In a slave-owning society, harbouring escaped slaves is immoral.
"Of course it's wrong to beat your wife!" says the person who beats their children in a society that has only recently ceased infantilizing their women (USA circa 1900 +/- 30 years).
"Of course it's wrong to own slaves!" says the person whose society only recently began protesting against and/or illegalizing slavery (USA circa 1866 +/- 10 years)
They say this not knowing that had the event of their births been moved a few decades in the wrong direction their morality would have shifted with it.
Those same people might have said "Of course its wrong to beat your wife with a rod thicker than your thumb!" or "Of course its ok to own slaves as long as you treat them well!" at the same point in their lives had they been born maybe 30-50 years earlier.
We currently eat animals as a normal part of our diet (for most of us, including me, anyway). To do this we treat the animals horribly. Incredibly badly. And we know it.
It's very easy to see how society's morals will probably change on this, in fact are changing on this, and how in 50 years' time our current stance on eating animals could be seen as monstrously immoral and indefensible.
Animals are not moral agents, and eating them is not different from eating plants. Both are part of the biosphere that we manage to our benefit.
And there are plenty of people who would vehemently argue that eating their pet puppy is very, very, very, different from eating a plant.
Good arguments, particularly in Australia, for eating wild pigs, clean skin bulls, camels, donkeys (mainly for pet meat IMHO), etc. Kangaroos, unculled, explode in number past the sustainability of their landscape and litter the ground with bones - humans estimate a cull target and shoot to reduce populations, only eating a few themselves (leaving many on the ground for "nature").
I will say though, I would only ever consider eating a dog in a life or death situation.
If there was no absolute need for me to eat a dog then I would not do it, and even if there were it would be a difficult moral dilemma for me that should I survive could possibly haunt me for life, but for my ancestors it was a common occurrence.