Professional sport is unique. The scrutiny. The pressure. The attention and focus. The commercialisation. The fame and fortune and rich finance. There are very few industries like sport, especially when you consider that normal individuals are often the stars, thrust into positions of great wealth, popularity and influence.
Because of the pedestal that they are placed upon, there is a very easy and painful trajectory for many: they fold under the pressure and mentally they suffer.
This is no different for Major League Soccer stars. Even those that have played in Europe and at higher levels than MLS will feel the intense focus that comes from the North American press and fandom.