I'm starting to notice more and more, when I am playing in 3bet pots OP as the preflop caller PIO suggest a raise/fold strategy often. For instance, UTG vs. MP 3bet on 7s4d9d, it likes 36%/7%/56% raise/call/fold. Its folding things like QQ no diamond and most non diamond non-pairs and raising most everything else. Another is MP vs. LP 3bet on 9JJ. Pio suggest raising 50% of range and folding 50% to 1/3 cbet sizing.
This concept is new to me. Can someone help explain the validity/strategy in it?
Is this generally always true (e.g. raise/fold)? Are there spots where its more call/fold?