The misunderstanding I see here is in the definition of “subjective”.
Subjective is often used interchangeably with opinion. And people can certainly have different opinions.
But the subjective that is meant is that morals don’t exist without a subject, aka a mind to comprehend them.
A rock exists whether or not a mind perceives the rock. The rock is objective. It is a physical object.
The idea that it is wrong to harm someone for being different is subjective. It is an idea. A thought. The thought does not exist without a mind.
So yes. Morals are all subjective. Morals do not exist in the physical world. Morals are not objects, they do not objectively exist. They exist within a subject. Morals subjectively exist.
That does not mean that any set of morals is okay because it’s just an opinion, bro. Because it’s not just an opinion. Those subjective values effect objective reality.