I think it's really silly to want to withdraw because you failed to qualify with a couple of incredibly mediocre songs and performances and then failed again with an average one.
Their vocals were absolutely outstanding, but the song, though by no means poor, was just another one in an already crowded field. Moreover, Vaclav looked tired whereas Marta looked downright bad. Her dress was ill chosen, the tattoo on the leg didn't fit the performance and made her look cheap, and she was too red in the face. Small things, I know, but they count for more than one give them credit for.
I was actually sorry they didn't qualify
instead of that irritatingly fake pair from Lithuania, but it was hardly a surprise