You’re doing a pretty good job for it being your 3rd language! I typically don’t see the “mind blowing” meme used in a sarcastic manner so he was probably being genuine.
PSA doesn’t call it Base Set, which is because (as already established) there is no formal name for it. I don’t know if it had a true origin other than being a nice colloquial name that eventually caught on. It apparently caught on and spread rather quickly as it was used in the making of Base 2. I can’t say for sure though, I wasn’t even alive lol.
Out of curiosity, I checked the old WOTC website for the earliest use of “Base Set” and it was being used as early as May 1999. Much earlier than I thought!
The Base Set is actually called ‘Expansion Pack’ in the Japanese release.
I’m unable to find the source I read a few years ago, but i.I.r.c. the first set in English was originally simply called ‘Pokémon TCG’, because they didn’t knew how popular it might become beforehand. But before its release fans were already calling it the Base Set. When it was officially released, it was still released under the name ‘Pokémon TCG’, but was called ‘Base Set’ by almost everyone in the community, and the name sticked. As I mentioned, I’m unable to find the source of this, but I remember reading about this about 1.5 or 2 years go somewhere…
Since the name sticked, it is now simply known as Base Set on almost all Pokémon related forums and wikis you look, and the Base Set 2 was an official name derived from this fan-dubbed name.