Quote Originally Posted by Pig_Vomit
I kind of get it but aren't we commiting a cardinal poker sin by giving away a free card?
No, we aren't.

It's LHE concept, where pot/bigbet ratio is so big, that losing some extra bets by overprotecting goodish hands is not that bad, while losing entire pot by giving freebie is one of biggest blunders . In LHE you want to maximize chances of winning the pot, when your hand gives you equity to fight for that pot.

In NLHE, postflop bets (and implied threat) are much bigger, than initial pot. Overprotecting with losing hand is more expensive, than in LHE, and main focus of extracting postflop value from losing ranges is much more important.