What do you mean? It's just an art style thing really.
That is the excuse that gets thrown nowadays to avoid the fact that most of the artists working on these shows haven't really had much (if any) education for the jobs they're given, and that irks me, to be honest. Artstyle should NEVER serve an excuse for hiding how to draw properly... Even if the show already didn't feature any proper shading or wasn't very expressive (when even Ultimate Spider-Man didn't have those issues, and they're both crappily animated most of the time) I'd still point out how bland, unimaginitive and hollow it looks. The last She-Ra reboot thing had the same problem (honestly a lot of cartoons in the past 10 years are very style-less or rely too much on other artstyles or being messy rather than crafting their own). It kinda drives away the notion that you must put effort into your artistry.
The issue with the anime influence is that most Japanese artists have been stuck with the rather inconsistent Disney inspiration they've carried for decades and can't differentiate their designs too much across their characters' ages (some can literally keep the same eyes or even heads for their whole lives, and the "it's an artstyle thing" could work in comedies but even in serious stories they have that), whereas it's basic education for most artists anywhere that drawing different ages is pretty essential (manga artists with more realistic styles thankfully don't have this issue).
Likewise over here we are taught how to draw different genders (because beyond our superficial features and right down to our very skeletons both sexes are quite different throughout the ages), something anime struggles with quite a bit when it's not sexualizing underage girls lol (no but seriously, how MANY jokes have been made in manga and anime where characters didn't know if X character was a boy or a girl? Far too many, honestly, it's a weird joke that's never had a punchline, and I'm pretty confident it's the artists' way of pointing out their artistic flaws, but without the intelligence to make that medium-wide running gag funny)
Bit of a rant I went through, unrelated to Spider-Man at that, but I'm working on getting a job as a comic book artist/writer (historietista where I live) and art in general has been a big part of my life, so I have a lot to talk about. My point originally was that this kind of art does not fit Spider-Man at all. Spider-Man is many things, he's bright and colorful, he's nimble and dynamic, serious and potentially dark but also cheerful and funny, he's a spirited youngster but also a responsible man, he deserves all the effort necessary and with what they've had to work with, damn near every show between the 60s and 2000s that featured Spider-Man has had some degree of effort to properly adapt Spidey in many ways (all the aforementioned aspects), some better than others (as is the case with TAS and Spec), and even the Ultimate cartoon had good designs from Ed McGuinness, an artist who has rocked drawing Spidey in the past (unfortunately his designs don't shine very brightly in that animation and don't quite match the jokey style the series has).