Sociologically, it's fascinating that the crowd instinctively reacts the way they do whenever Falcon Punch / Warlock Punch / similarly "disrespectful" move is used. Interesting that the mere concept of the move generates that kind of shock and awe, irrespective of whether or not it hits.
The more I watch this, the more I think Falcon has no response to Sheik. The commentators mentioned that Falcon is a heavyweight and a heavy-hitter, but the fact that he has to commit the way he does means Sheik just has too many options to open him up. Kind of a different extreme of the Ganondorf / Doc effect, where the fast yet read-heavy character is beaten by the significantly faster, hyper-safe character.
I think it's because those moves are really telegraphed, so you kind of get this bullet time effect where when a person is getting hit, it feels like their life flashed before their eyes. For instance, people don't get hyped much when Melee and Brawl Falco lands a Dair, but in Smash 4, where it's much slower, when someone lands it, people get hyped because it's telegraphed, it has hit lag which creates a pause as if that move hit so hard, time has to stop to understand what happened, the amount of knockback caused by Dair right after hit lag makes it look even more amazing, and people just don't expect a move like that to connect because of how slow and butchered it is compared to Melee and Brawl Falco's broken Dairs.
They're suspenseful and that's what moves like Falcon Punch, slow spikes, and moves with hit lag like Marth's tippers or Ryu's everything. So, when a Falco lands a Bair, it's like, "Oh ****!", because it's so fast and the opponent usually instantly dies at higher percents, but when a Marth lands a tipper Side Smash, it's like, "Oh, did that..", this is where the hit lag happens and right when it launches, "OH ****! TIPPER SIDE SMASH!" A move like Falco's Bair is so instant that you do register it, but not in a way where you have to think about what just happened unlike a Marth tipper Side Smash, a Shoryuken, or a slower move like Ganondorf's Volcano Kick or Ike's Eruption. Ganondorf and Captain Falcon are loaded with moves that build suspense or are fast and strong enough that people just don't register what happened. In contrast, characters like Sheik, Mario, and Fox don't really have much. It's just, "Mario killed with an Up Smash", "Fox Baired someone", and "Sheik things."