They are the second youngest team in the league. That fact does get lost on a lot of people. It doesn't mean it's okay for them to play like shit. But there is something to be said about being inexperienced, particularly being in this scenario.
The last 2-3 years, this team was out of it by game 45, so they've been playing loose hockey the second of half of the year for a few seasons. This is the first time in a lot of these players' young careers that they're in this position.
Also, quand qu'on se compare, on se console. The Blues went on a 12 game win streak. They had opportunities to lock their spot, but they lose their last 3 games and they haven't clinched yet. Meanwhile, while they lost, Flames won, so they are 2 points behind STL and have a game in hand.
This is the reality of the wild card race. It often comes down to the final game of the season. Last year, Caps clinched on the last game of the year.