What if we don't?
Merckx was caught three times anyway.None of this lets Pogi, UAE or Gianetti off the hook but objectivity is important. Merckx was still more ridiculous and there were none of the "methods" and sophistication around back then that we suspect today. I think blood doping had been tried but I haven't read anywhere that Merckx was into that or that blood doping was responsible for his records.
But I am glad there were no online cycling forums back then
Objectively Pogacar is still a long way short of Merckx best seasons. Below tables are from PCS. And according to a Google search 1969 wasn't Merckx best year - 1972 and 1974 were.
Also check how many racing kilometres and days Merckx was doing compared to what they are doing now (assuming Pog is typical for the top riders today):
Pogacar 20249959 km in 58 days | PCS points: 4588 | UCI points: 11655 2025 (7-Oct) 8394 km in 49 days | PCS points: 4646 | UCI points: 10880 Merckx 197415958 km in 93 days | PCS points: 5564 197314655 km in 87 days | PCS points: 5707 197214385 km in 80 days | PCS points: 6275 196912145 km in 73 days | PCS points: 4734
Consider the opposition.
Many races looked more like a Belgian championship.
LBL 1969: 7 Belgians in top 20.
MSR: 1969: 6 Belgians in top 10.
Amstel 1969: top 7 (!): all Belgians and only two nationalities in top 20.
Omloop Het Volk 1972: 18 Belgians in top 20
Tour of Flanders: 9 Belgians in top 10.
Merckx basically rode against regional opposition.
I don't know how the km are relevant in this story. Considering most riders in Merckx era rode similar full programs, Pogacars domination is even more remarkable. There was very little specialization in the Merckx era.