Pulp fiction was fiction written for the popular pulp magazines of the 1900s through roughly the 1960s. Those magazines don't really exist anymore. The "modern equivalent of pulp fiction" -- which is to say, the modern equivalent of writing for the pulps, writing to earn a quick buck -- is self-publishing low-effort fare on Kindle Unlimited or something similar. So the guy you were responding to made an apt comparison, IMO.
Interestingly, the pulps that are still hanging on -- like Asimov's Science Fiction Magazine, and like various other fiction magazines -- are today characterized by a very high standard of literary quality. On average, miles better than the self-published Kindle Unlimited stuff that rates highly (for some reason) on Amazon.