I think “most” is safe to say. Especially with the caveat of US citizen Americans. I expect that there are regional differences, as well. My cousin in Maryland played lacrosse in high school. There are people in the south who have never heard of lacrosse.
I have one friend that will watch pretty much any sports game, probably (at least partly) because he is woefully not dexterous. If there is a game on somewhere that he can stream, that is what is going to be on his ‘background noise’ monitor. Otherwise, it’ll be Pandora or Spotify. I haven’t asked, so I can’t say he likes soccer specifically, but I have seen soccer playing in his office.
Other than him, I do not know of any non-hispanic friends of mine that like soccer, that watch ‘pro’ soccer.
*Grade school little leagues are another matter. But even then…
My sisters played soccer in elementary and middle school, but neither are soccer fans now. Since Houston has a team, I’m sure if they got free tickets to a Dynamos game, they would go, but using free tickets to a live event could be considered a social event. To me, that’s not the same as seeking it out, following along as a fan. For example: My wife has zero interest in motorsports, but if I got tickets to an Indycar or NASCAR race in DFW, she has said that she would go with me, because it would be a new experience.
I know there are Dynamo fans in Houston, but there is often a difference between supporting your local team and being a fan of the sport overall. I have Formula1, Indycar, and NASCAR races on my phone’s calendar. I have watched Australian V8 Superboat jetboats racing on an indoor obstacle course. I like motorsports. In comparison, I follow the Astros, listen to their games on the radio and go to games when I can, but overall, I would not call myself a huge baseball fan. I scan results to see how the Orioles are doing, but I don’t stream their games. I’ve never been to a Dynamos or Texans game, and have next to zero interest in soccer or football.