I have heard this several times, but either I do not understand it or I disagree. Do you mean parsing the output of the ls program? Parsing ls output is not wrong, the program produces a text stream that is easy and useful to parse. There's nothing to be ashamed when doing it, even when you can do it in a different, even shorter way. I do grep over ls output daily, and I find it much more convenient than writing wildcards.
One can certainly do fine by grepping ls output in one-off instances, but I'd be really hesitant to put that in a script.
For given paths, stat command essentially lets us directly access their inode structs, and invocations are nicely concise. The find util then lets us select files based on inode fields.
Both tools do take a bit of learning, but considerably less than grep and regexs. Anyway, I've personally found find and stat to be really nice and ergonomic after the initial learning period.
