Well, if for example Saudi king donates you tens of millions of dollars to your campaign [1] and you win thats perfectly fine, but you lost and then 500k of funny ads bought by some bogus/fake companies is in your words why you lost. Not even funny. And saying facebook is part of it is even more stupid.
On the other hand I never understood why for US citizens it is perfectly fine for political persons to receive millions in donations from corporations. Where I come from that is considered bribery by default and that politician would be in problem.
[1] https://theintercept.com/2016/08/25/why-did-the-saudi-regime...