I think the way to determine whether a moral is itself good or bad is to think of it in pragmatic terms. A reasonable thought experiment to evaluate the moral is to force it on another social group, such as ants, monkeys, or bees. I know, sounds weird, give me a chance ...
You've got these ants in an anthill. Obviously some morals are necessary ones - it wouldn't be terribly productive if ants kill each other, they couldn't really function as a colony if they went around doing that all the time. It isn't very productive for them to leave dangerous trash that has lots of bacteria and things in their nesting sites, so yeah, ants are environmental activists, all colonies create areas where they dispose of organic wastes, they keep their nest clean. On and on, etc ... ant morals.
But some morals when you force them on ants are just stupid ...
Human moral: Don't bury plastic bottles in the ground because they will be there forever. Well, who really freaking cares if a plastic bottle is in the ground forever, what harm is there in it ? Rocks are in the ground forever. Plastic bottles aren't causing any harm being in the ground forever. Yes, plastic breaks down in sunlight and becomes little bits of plastic that can get caught in an animals eyes - well so what, so do rocks, they break down in freeze/thaw cycles, and animals get rock grit in their eyes, that's why they have tears, to wash it out. This knee jerk hatred of plastic bottles is a moral, but it's a stupid one - if ants had a plastic bottle in their nest it wouldn't matter to them, it doesn't have any harmful bacteria to harm them, it is completely inert, it just doesn't matter. This moral is about people just not liking the sight of pop bottles, but plastic PET bottles are too valuable to society for storing liquids to get rid of them, they are a boon to humanity.
Human moral: Don't build nuclear reactors, they are bad. Again, thinking of humans more as ants than people, is this a good or bad moral to have ? I think this one is still out there for discussion. Obviously it has a good side and a bad in terms of pragmatics - the energy generated is terrific, it's a cheap form of energy that doesn't require much in the way of drilling, mining, etc, though there is some mining. But the radiation is a human toxin, and we humans do have two accidents we can point to where radiation did leak out and in one case it was a major disaster. Is nuclear energy just inherently too unsafe for us to rely on, is the toxic nature of the fuel and process too much for us to deal with ? In terms of ants there is obviously no parallel, but what if there was a parallel, what if ants did rely on some plant to give them something they use, but it was toxic to them ? Can be debated.
Etc ...
My only point here is that morals do serve a purpose, they are convenient rules of thumb that help human civilization function. Without any morals we'd just descend into chaos, which kind of appeals to my anarchist nature, but probably wouldn't appeal to most people.
Most "morals" in today's society are not pragmatic necessities, they are just one groups desire for tradition, or some groups need for recognition, etc, they serve no overall purpose other than to force other people to do what a subculture or group wants to do. When you force these morals on humans as a species and take the culture out of it they are absurd - that we should dress in certain ways, have sex in certain ways, paint our houses in certain ways, etc, these are the least important kind of morals, or even harmful ones, because they serve no pragmatic good. By serving no pragmatic good they become a burden on society because they have a cost in terms of time, energy, resources, etc, but have no beneficial result on people's lives which makes them a parasitic drain.