You'd have to time warp Pogacar to the late 60s early 70s to know and, vice versa, Merckx to the 2020s, but this is impossible, so only the stats are relevant.
The number one is the Tour winner, which hasn't been Pogi for two years.
Without arguing with the content of your statements itself, I'd like to point to their inherent contradiction.
You can't claim only stats are relevant and in the next post dismiss the only officially agreed stats on cyclist rankings.
You can say these are the wrong stats, but then we lose objective grounds for comparison and we're back to the point where you claimed only stats are relevant, because we can't compare cyclist with other (subjective?) measures.
Now if we go into the content... There were some multi (more than 2) tour winners in the last decades. For none of them has there ever been a debate (even thoughts of comparisons were shunned upon) how do they rank compared to Mercx, then Pogačar arrived and put the debate on the table, where we are now.
This goes to indicate, that tour wins are not be-all end-all in this discussions. There are numerous other things, for example like the nationality... if Remco was from Slovenia, his thread name would never mention Mercx (even as a joke)... We have cycling legends from Italian history that never even started the tour, etc...
So what actually matters with regards to how something is written in history (that then still has a life of its own) is how people at the time (subjectively) perceive it, and there are quite some people who see Pogačar as a possible challenger to the goat status when all is said and done.
Maybe instead of trying to prove them wrong with some (quasi - by your subjective measures selected) objective stats, you should try to consider why do they think this way. When you will understand their point of view and still be sure they are wrong, you will at least have much better understanding of how (many) people think (in a more general sense than just cycling-goat debates).