I think it's perfectly fine (good even!) to praise people for correct predictions, but I do think it's wrong to crap on people for wrong predictions. For example, TheFlatLannister deserved to be praised because on that Reddit thread he said "no way DP x Wolverine makes less than the previous two movies" and he ended up being completely correct.
Deadpool 3 doesn't have holiday legs like No Way Home.
And No Way Home had the luxury of being the first big event in two years and having a pent up demand for experiencing something like that in the cinema.
Dude even I fucked up, I thought this movie would underperform. But this is Super Mario 2.0. The most obvious blow up ever that people decided to underestimate because "oh this completely unrelated movie didn't do well."
But he's not wrong. 600-700 might actually happen