When the Chinese government is frivolous with blocking access to websites and services, it's not a huge leap to worry they may be frivolous in denying access to other services they provide. Anniversary of the Tiananmen Square massacre? Maybe we'll bump down the resolution in that area to make protests more difficult.

Not saying they're going to do it, but just the smallest uncertainty means you'd rather trust one of the 3 other competitors in the area.

edit: I wonder if putting keywords on this page will get them denied access to these comments 六四事件 天安門廣場抗議 天安門事件