Weak players make postflop mistakes: Against weaker opponents, you generally want to play more hands, especially in position, so you can capitalize on their mistakes. Folding too much from the blinds means missing out on +EV spots.

Weak players often open too wide: Many weaker opponents have wide opening ranges, which means you can profitably defend more hands against them, rather than folding more.

Exploitative strategies focus on aggression: Instead of tightening up, Fedor often flats more in position, 3-bets more aggressively, and applies pressure postflop to punish their leaks.