Yeah, this is true.
Indeed, there was somehow an encouragement in making icons - much more realistic - than - more cartoonish. But it was somehow encouraged a long time ago.
I can easier draw somethin' realistic than somethin' cartoonish, but this doesn't has to do with my moderation.
I think there must be a balance, not overly cartoonish or too realistic. Ofc, it may be enough variation between them, let's call them "limits". And, my taste doesn't matters in icon approval. I approved enough icons, that i personally don't like, but which meet the criteria for approval. So i don't approve icons according to my taste. Actually, i like as well the two styles and generally it doesn't matters that much to me - the style - but rather - that the icon is well done and harmoniously.
That doesn't stop me from doing comments like: "too cartoonish" or "too realistic". Just thinking that, there will be a big difference between them and will be clashing if somehow they would be used together.
Also, i can't approve all the icons with 4 or 5. And i can't do a thorough study to explain "why", because my time is limited and there are enough tutorials and rules that explain quite clearly what quality conditions must be met, etc... But, i can say precisely that - for each icon approved with 3 - there is room for improvement. I try to be as objective as possible. Also, if i was not clear enough, contact enjoy - (she being administrator and having much more experience as icon moderator) to explain better to you, what are the criteria for approval and why we claim that the icons are cartoonish.