Casuals aren't intimidated by FPS like they are fighting games so yes it does just pertain to fighting games. Fighting games online are ZERO fun for noobs. They get slaughtered and the learning curve is way steeper than in FPS titles. At least when they are initially slaughtered in FPS they are able to learn from their mistakes far quicker because of less emphasis on execution skill and inputs in the genre. There is still skill needed but its not nearly the same type of stuff as making up combos, performing resets, and blocking mixups which is shit casuals just never really get into without a lot of help. Fighting games require a long ass tutorial and a dictionary of terminology and concepts to get folks over the hump unlike FPS.
Apples to Oranges comparing FPS to fighting games.
It is also the teamwork and the environment. I used to visit a net cafe and it was packed with kids and teens who made teams playing with each other or against other players. MMORPG games as well.
In the case of Overwatch it was also much more affordable to play it in that environment, rather than paying full price and being limited at home (homework, parents etc) and usually with a low quality PC/laptop.
It also had consoles so they could play sports games.
But while sports games rely on real player licenses and FPS rely on teamwork, FG would rarely fit in that environment, in contrast to the arcade days.