Average attendance of MLS is higher than average attendance at NHL games. I would still say that the NHL is more popular, but MLS also isn’t the most popular soccer league. There are tons more fans of EPL, Champions League, and international soccer.
Polls and surveys also show that soccer is generally more popular than hockey in the United States.
Even on CB, there seem to be far more soccer posts and threads compared to hockey. Obviously that’s shifted a bit lately because everyone needs to give their name suggestion for the new Utah franchise. But it’s not that obvious which sport is more popular.