You've only heard on ThinkPad having it because it's most easily encountered problem. HP, Dell, ASUS, Fujitsu, Toshiba, VAIO, ... they all have it in some model

You've only heard on ThinkPad having it because it's most easily encountered problem. HP, Dell, ASUS, Fujitsu, Toshiba, VAIO, ... they all have it in some models and not on others. But Dell users don't swear by their Inspirons or maintain LatitudeWiki. White-box suppliers/resellers like Clevo or Walmart, or more recent entries like Microsoft, Huawei, Razer, Valve, etc might not have it across the lineup. Whitelist feature also invites people break root of trust; that might be an alternate concern for those brands too.