I think ethics is a personal thing. Just like religion, sexuality, choosing a hockey team etc. there is no right or wrong answer it's just a personal choice.
But, for what it's worth, you have answered part of the question. I seen way too many dead fish on the bar with their bellies cut open and the roe gone. Ditto people bonking females for the roe but releasing males. Can't be good for the ecology. Most serious duck hunters will only kill males to help the reproduction cycle. The crab fishery has a no female retention rule so there must be some scientific reason not to selectively kill only females.
Fair enough... Not to stir the pot or anything, but the chilliwack hatchery (and most hatcheries) receives well above and beyond their broodstock target each and every year, and the surplus is collected and given away/sold anyways, so one might argue that many of the female hatchery fish people may/may not be picking through are not going to make it to spawn anyways. Also, I believe the hatchery uses wild only for their brood (maybe someone could clarify).
Nevertheless, I would have to agree with you that far too often guys bonk only for the roe and leave the fish behind which is unethical. But I still love fishing roe when I have access to it and can obtain it ethically