The user didn't point it out that tho. Reaching puberty is the age of consent according to the Quran and Aishas age isn't a fact like you present it as. Marriage and intercourse are two different things in islam. Idk what you mean by justifying it. It was a societal norm, not only in the arab deserts but the whole world that practised in now what's called child marriage. This is general knowledge.

There was no school or any other societal structure that kept kids separate from adult responsibilities back in the day, so comparing the age of consent now vs then( as long as just a century ago) doesn't make sense. Differentiating a man vs a boy was decided by his mastery of trade he was apprenticed in. A girl and a women, periods.

You could ask the same question about the bible which set the societal norm of this exact context. Or judaism which goes even futher to state even while things which I don't want to say cause I don't want to get banned. Do not say this is whataboutism cause it's not. The arabian peninsula was indeed heavily influenced by judaism and Christianity before Muhammad was born.

Edit: forgot to add that it's not a practise anymore except some extremist groups like the taliban and some remote places like in yemen.