I submit to you that your line of reasoning is the problem in the world today. Instead of using logic, reason, and probability, humans are now resorting to saying "There is no proof of........" and of course there isn't. OJ Simpson got off because some jurors thought cops hated blacks and planted evidence, ignoring bloody footprints from Bruno Magli shoes, blood in his car, and mounds of other circumstantial evidence. I use the resurrection as an example because as ludicrous an idea as that is, no one can disprove it. If we always demand 100% proof like an unaltered photo from a home video camera showing a guy stabbing his wife, we will never get anywhere.
Yes, Russia is not above spying on us or even tinkering around to try to make someone win. But what is the likelihood that they would resort to social media posts and did when no one that you know of, or I know of, saw any such mean posts. Is it more likely the FBI, known Trump haters and assassins, claimed that or that it happened? Remember, this is the same group who infiltrated Twitter to demand conservative posts be taken down.