There's no reason to laugh. None whatsoever. No reason at all why fans of the New York Red Bulls should be amused or even moderately cheered at the playoff misfortune of another team.
RBNY's 2016 MLS playoffs ended in a fair-and-square loss to Montreal Impact. No great complaint; certainly no reason to celebrate some other club's achievements in a completely different playoff series.
The NYCFC-TFC Eastern Conference semifinal only had relevance to RBNY if RBNY managed to get by Montreal to face one or other of those teams in the Eastern Conference final.