Sorry to hear that. In your defense, had I found a glitch in an online blackjack game that turned the odds in my favor I would have a hard time not pressing my edge. My rationale for withdrawing winnings rather than upping my betting would mainly be with the site possibly not paying out due to the glitch and wanting to cash out winnings before they froze and confiscated them. Now that I reread your post, it's actually a bit unclear, did you go on a bad run and lose or did 5dimes confiscate your money?
I lost a lot after Full Tilt was insolvent. And some other random poker sites that never paid out.