Facebook CEO Congratulated Trump on 2016 Win After 'Innovative' Social Campaign
forbes.com
forbes.com
That makes an important distinction compared to "all major US candidates".
So you see, when the boss of "Advertising 'R Us" calls me to congratulate me on my promotion it is not newsworthy. It is when the POTUS is congratulated by the very same person who later admits his company allowed foreign powers to influence the election of said POTUS, and for the same type of actions that were later attributed to those foreign powers.
It's how the news work.