So, not "Apple is Apfel and it's masculine" but rather "'The apple' is 'der Apfel'".
The reason in part is because if you start learning two gendered languages, like German and French, sometimes the genders are different.
Apple: Apfel (m), pomme (f)
The gender and the word are a bit detached here. If you can memorise them with their gendered article, though, and get used to the sound of it, it can become much easier to recall it reflexively, with auditory memory helping.
Apple: der Apfel, la pomme.In theory, you would not encounter the wrong ones in examples:
Whereas if you remembered it as Apple -> Apfel, m, pomme f, it can be easier to accidentally swap the gender, since they're just generic labels shared by the two languages.
I am using duolingo.com again to review my German and to relearn French. Mwahaha.