Still we had a peak of conventional oil in 2007, I don't get why I'm getting downvoted for that fact.
I don't think you were downvoted for that; instead, I think you were downvoted for saying "This is wrong" when GP commenter claimed the peak oil has been predicted decade after decade. GP also just said "peak oil" not "peak conventional oil" so I'm unsure why you brought up that distinction?
A better reply might have been "Peak oil has been wrong decade after decade, but current projections are somewhere between 2025 and after 2050. Additionally, if we restrict it to only specific geographic regions, or to only a subset of oil extraction, it occurred in the mid-2000s instead of the original global projections of between 1922 and 1960."
I'm not the one that downvoted you.