"He obviously took hurting her, even killing her, lightly. Men do this all the time - that is not an exaggeration."
I'm not sure that is obvious. If you believe his version then it doesn't look like he took it lightly. If you don't as you clearly don't then yes it does look like he had a lax attitude to hitting his wife.
"Isn't it fair to say that the kind of blokes who kill their partners perhaps have a less than great attitude to the value of those partners' lives? Maybe they think they own them? If you don't hit your wife round the head, why not?"
On a broader discussion yes it is, obviously anyone who hits their wife doesn't value them and has issues. As for this specific case I'm not sure what your point is because once again it will come down to the same thing as above. If you believe that she was throwing plates at him then you could argue she had similar disdain for his well-being as he did for hers. If you don't believe she threw any plates then yes as above he obviously didn't value her at all.
-"I am not willing to take "then she started throwing plates at me" at face value because this is the salient detail that led to this being classed as retaliation, instead of just plain shocking violence."
Just on this point, have I missed something in the article linked. where does it say this lead to the attack being classed as retalliation? I thought it said his claim of self-defence was rejected? Not trying to be pedantic, genuinely interested as this would be a major fact. I would have thought the reason for not charging murder would be that it would have been almost impossible to get a conviction on such a charge.