― Kurt Vonnegut, Mother Night
And if you kept posting it long enough, and participating in that community long enough, it's very likely there would stop being a meaningful difference between what you posted ironically and sincerely.
It's like trying to influence NRA members trying to make them think that guns are cool.
Also, while the extremists might not be able to vote in numbers to turn an election, they can definitely make the internet a sufficiently unpleasant place for discussion that they have a chilling effect on support for everyone else.
Many Clinton enthusiasts were hounded into "secret" or private subreddits and Facebook groups because of the intensity of abuse they received. Most of the more leftist and Bernie Sanders supporting spaces were, likewise, spammed with so much FUD content that it was impossible to have a productive conversation about anything else. They were a seriously disruptive influence on the capacity for anyone else to organize.
Similarly, arguing about rally sizes may be a fun political argument but ultimately it comes down to 62M votes for Trump and 65M for Clinton, so it's hard to say there was a huge difference in the number of people who supported each candidate.
However, I'm still waiting for Russia to massively benefit from the Trump administration.