For clarity I just mean watching hockey. As far as American sports go hockey is so much more appealing than football or baseball. It has all the suspense of baseball, the speed of basketball, and the physicality of football plus everyone's skating. Plus they're not constantly taking penalty shots and pretending to get hurt like in basketball. Also strangely enough illegal hockey streams are the only ones I've seen where no one is saying racist/homophobic/transphobic/other reactionary shit.
Personally, I like set piece plays, which football has.
More generally, I think one factor might be that ice hockey takes a much more particular environment that other sports. Football, soccer and basketball are all easy to play with your friends growing up all over the country.
Another question: why isn't field hockey a bigger sport in US? Also, why is field hockey a "girls sport" in US?
I know very little about field hockey. I think it's primarily a "girls sport" in the US for the same sexist reasons softball is a "girls sport," that is, people see it as being less violent and dangerous and thus "more suitable for girls." Where I grew up we had a uniquely strong culture around girls ice hockey and hockey was generally more accessible than for people in warm climates so I considered it more egalitarian than other sports. Also lacrosse was the stereotypical rich kid sport, along with American football.