>So, does this apply to URLs? The fact that these regexes are....so huge...makes me think that something is fundamentally wrong
Yes, if your regex is above {.../50/100/...} characters, then write parser.
I struggle to understand why do people write those crazy regexes for emails, urls, html when probably in all popular technologies there are battle-tested parsers for those things.
Sometimes you're given an arbitrary bag of bytes with best-effort well-formed data. Regexes are gross but quite good for those cases where you need to try to rip out some bits from the data abyss.
Yes, if your regex is above {.../50/100/...} characters, then write parser.
I struggle to understand why do people write those crazy regexes for emails, urls, html when probably in all popular technologies there are battle-tested parsers for those things.