I don't care what other hobbyists do or don't do. When asked, I'll give a response I believe to be appropriate to the subject matter.
Finding a post listing a pH range of 6 to 8 for any non-migratory fish is cause enough to pause and think as to the validity of such a claim.
BTW, anyone can search around the net long enough to find the answers they want to see instead of an answer they need to see. Here's the end result of a quick 5 minute search on the pH preferred by oscars:
Mike Edwardes Tropicals: Oscars
Water: 16°dH, 8°KH, pH 7.2.
Cichlids.com
Water
Ideal temperature: 20-26 Celsius, (70-80F)| Water chemistry: Most water conditions tolerated, prefer pH 6.5 - 7.0 (Soft to slightly hard)
Age of Aquariums
Name: Astronotus ocellatus
Size 35 cm
pH 7.2
GH 10
Temp 26°C
Origin: South America