Adding “crypto-” to the beginning of a science does not automatically mean that you have created a new and genuine branch of real science that has legitimacy and respect among real hard-working professional scientists. If that were so, a science-fiction author could be a “cryptophysicist” (analyzing physics in a world that does not exist) and a mystery writer could be a “cryptocriminologist” (analyzing crimes that never happened) and a guy who watches House MD every week is a cryptodiagnostician (diagnosing fictional patients). If you ever imagine to yourself, “I wonder what would have happened if Hitler had won World War II?” then you’re a cryptohistorian. And if you tried to figure out the stick figure code from the Sherlock Holmes adventure “The Dancing Men” you’d be a cryptocryptoanalyst.
You may be engaging in cryptophysics, cryptomedicine, or cryptohistory, but that doesn’t automatically make them respected or legitimate fields of study.
But that’s just the *term *“cryptozoology”. There are legit scientist out there hunting for “lost species” like the Ivory-Billed Woodpecker and the thylacine. Hunting for a “lost species” is not disreputable. Calling yourself a “cryptozoologist” is. And that is just recently- certainly Bernard Heuvelmans and Willey Ley were both respected scientists. I’ll point out that many legit scientists poo-pooed the idea of the giant squid being anything but a legend.
Thus, it’s not “bad science” it’s just terminology.
"Cryptozoology is the search for animals that are rumored to exist, but for which conclusive proof is missing. This includes the search for living examples of animals that are known to have existed at one time, but are widely considered to be extinct today."Cryptozoology - Wikipedia