The halachos of not throwing food are found in the Shulchan Aruch Siman 171, seif 1.
It says there that you are not allowed to throw bread, and you are not allowed to throw other foods that get ruined when you throw them, but you are allowed to throw other foods (meaning anything but bread) if it something that does not get ruined when it is thrown such as nuts or pomegranates.
The Mishna Berurah there (s”k 10 & 11) explains that you can’t throw something such as figs because they are soft and will get mushed and t/f ruined when they are thrown, but nuts and pomegranates are okay because they are hard and do not get mushed when they are thrown.
I don’t think that apples get mushed when they are thrown. They clearly remain edible since the Chassidim eat them. So it seems that this whole thing is completely muttar and there is NO basis for saying it is assur.