Can any statement be morally and logically defended from two different perspectives?

Okay so I’ve had this idea/mindset going on for a while that literally everything is subjective… there is no universal good or bad. I’m taking philosophy classes in high school right now so I don’t think I am exactly fit to assess my own thoughts. I thought I should ask this Reddit if there are any arguments against my idea.

I’ve had a discussion with someone about Charles and Camilla in The Secret History. They had a romantic and sexual relationship with each other despite being twins. I was asked if that was a wrong thing, to which I answered: “As long as they’re not going to bring a child to this world that could have significant problems (deformaties or any of that) that would affect the child’s quality of life, it would not bother. In addition to that, if it were real life, them having such a relationship would not negatively impact me.”

I have an uncle who divorced my aunt and went off with someone in his own family (I’m not sure what the relation was but it was someone in his family I believe). That happening of course impacted my aunt, and therefore impacted me because I’m close to my aunt. Him doing that hurt her. So basically what I’m saying, if something doesn’t hurt/negatively impact me or someone I’m close with I would be okay with such a thing, even if they’re literal twins dating. They can do whatever they want and I shouldn’t intervene with that.

However of course from many religious point of views you can absolutely say that such a relationship is morally not okay at all. Which as far as I know is a logical statement as well. It’s all about their own values and morals.

I don’t know if you could attach proper logic to such statements? I haven’t tried it… but based on what I’ve explained so far… am I going in a totally wrong direction with this or not? Because I don’t think my argument or the other argument itself is universally right or wrong? Do any of you think everything is subjective because it can be morally/logically defended from two different perspectives with different opinions?

I don’t know how many people here on Reddit read such long posts… but if you came this far… thank you so much for your time and I appreciate you helping me out with this! Enjoy the rest of your day!