I agree with most of what you said but the reason why they immediately became a pair is because of the fact that Leo NEEDS it. Having a mate has psychological and physiological benefits for them. They mentioned how suppressants has really bad side affects on Leo and that in the past he slept around a lot was because having sex with an alpha helps with the heat, but since having sex with Iori his body rejected all the other men since it recognised Iori as his Alpha. Becoming a mate is Honestly just the best thing for Leo. I too wish they didn't bond at that age but considering the facts that suppressants makes him hella sick and if they bond Iori will be the only one to be affected if they mate I believe its for the best. And they're fated mates too so it's better for them to be together. Maybe if they met a little bit later in life where Leo didn't have any bad side effects with the suppressants things would be different and they could've done things the right way.
Don't get me wrong it's way better than the basic common drivel we get from the omega Verse genre with lots of you know rape at least the alpha was a green flag and all.
one of the reasons is the ending I found it funny he wanted to get married, and he was mad he had to wait till he was 18, but as alpha, he got to make a permanent decision for the rest of leos life by placing a permanent scar on him? marking should happen till after they were 18 he should have waited a couple years after he built faith with the uke to show through his actions and through time that he was going to be there for him.
that they didn't have to be MATES for that to happen and I was disappointed that he just said a speech of words and Leo fell for it. I kind of felt like the Arthur disregarded Leo's past and it could have done been way better and more romantic they could have had sex yes but they didn't need to do the marking . and then leo as afraid when the bite happened honestly, I like it when there's complete trust and love when the marking happens it just irritates me cause I was hoping for something different at least with this.
fated pairs is just the perfect biological pairing and that you just get dopamine just from touching each other, when it should be more of a relationship based on feelings all
that extra chemistry stuff should be a bonus.
And ironically I like the alpha better than the Omega in this story the Omega annoyed me with baiting him with sex and I understood his whole situation it's just that he felt very disrespectful, bodering on dub con It doesn't matter what your past is because a lot of people have the same history it matters what you do with it and you can't use us it to excuse your actions
sry for the rant