well, let's take the same argument. for someone like that who's very strong at english but fails maths, they could also ask you the same thing. to them, English is also piss easy, then how are you failing it? if they can get a band 5 in english and still fail in maths, then why can you, someone who does well in maths not get a band 6 in english?
they're different courses.
you can also argue it's because your forced to do english which you're not as strong at, and they had the option to do maths. because english is a mandatory course which EVERYONE does, which also heavily depicts ur atar because its able to be a measurement of everybody else in the state, you shouldn't be relying on your other courses to bring up your english mark...
"There are enough intelligent people in math advanced, who also do good in English, that boost the scaling of math advanced."
i mean, i'm not affected bc i do ext 2, but would you also affect the math advanced scaling, because you did bad in english as well?
i'm not saying you're entirely in the wrong, or whether there is a right or a wrong. i'm saying, you shouldn't be needing to judge everybody else and blame everyone else for something you could have fully controlled yourself. had you spent more time diligently preparing and studying, you would've been able to get better marks, and be less affected by such restrictions