They behave as if doubling down is the only gambling move out there.

Double down

phrasal verb of double

US

  1. 1.

    strengthen one's commitment to a particular strategy or course of action, typically one that is potentially risky.

    "he decided to double down and escalate the war".

  2. 2.

    (in blackjack) double a bet after seeing one's initial cards, with the requirement that one additional card be drawn.

    "the amount only increases when you choose to split or double down".