It has to do with cartoons being based by the realistic human traits. The easier way to see this imo is comparing their kid cartoon shows (pre calarts) and how they animate/show things. Though both are simplified, most cartoons will show every zit/booger on a character or anything 'unpleasant' as well as detailing them. Anime on the other hand will be more 'cutesy' in their nature. Even if they have those snot drops on sick characters, it'll mostly be just a flat symbol.
To go back to the main point, the audience can feel more empathy/emotion because those cartoon characters have more connection to reality than anime. Now of course that doesn't mean anime is bad or some other extreme idea that wasn't put any thought into, anime does have its benefits that cartoons don't have. Its hard to describe, but its good at "superficial" beauty and the prettiness/idealistic fantasies. Best example to describe it is the 'chuuni' trope common in anime; like those cool fight scenes/explosions characters do with their 10 ton swords wielded by anime highschooler #3242, the stories are shallow as a YA novel, but it 'makes up for it' or focuses on the visual impression (which one you think its trying to do is up to your own conclusions).
For example in the intro scene of Up by Pixar if you were to redraw the characters in the standard anime style, its easier to cry in the cartoon one because we have more of a familiarity in it (from the reality/realism we are constantly in contact with). If this wasn't a universal human thing, then live-action dramas etc. wouldn't exist in Japan etc.
The anime vs cartoon debate is null due to the preferences of the audience. And of course there can be anime out there that does a good job of conveying human emotions vice versa or other rare cases; I think its more of the two mediums doing their best when they can exploit their advantages and serve their purposes. Also this does not mean that anime is worthless because its escapist/superficial too; both can (and must) exist, and focus on their audiences who can freely switch around from what they want to watch, as well as letting creators decide wtf they want to do at the end (or how much they want to pursue money vs quality)