Are they art tracers?

Okay there's something that's been bothering me for awhile. It's this person I've met online, they don't really post much of their works online but their post made it seem like they did something really good. I'm not sure if they're just heavily referencing or tracing, since I'm not in control of their personal life.

There's also this classmate of mine, she traced a lot of artworks and didn't even dare to credit what she used as a "reference"
And yes, a friend told me this because she was her best friend. They might be best friends but tracing art without credit is still bad.
She later found out some original images my classmate(suspect of tracing) got from. There's also this guy from a grade higher from our class and copied few arts and didn't credit them either. They might take it for "inspiration" or practice but it's really important to credit the og course and not just claim it like you created it all by yourself. And yeah that's pretty much it

Do you think they're art tracers? I've seen some of their works heavily referenced but didn't credit the original source. I might be overthinking it but it really bothers me.
Tracing and self claiming it is really wrong. You can trace or use reference for practice and to understand but redoing it like you own it is just....
wrong... (ノ_╰)

Sorry if I wrote something this long, no one's really listening to me somewhere else