If someone walks upto me in the voting booth and says "vote for X or I will kill you" that's a crime. If they do it in the pub it's probably a crime. If they do it online the police don't have enough manpower to deal with the situation.
We should change that.
Every time some fuckwit tweets "you and your kids are going to get raped to death and I know where you live" because some woman dares suggest some political chnage I would like to see jail time.
And if we do that then I can understand your argument, but I would then say it is not valid - in a society that protects free speech.
Much more likely is that I'll vote ignorantly because I lack information that someone withheld because they're intimidated by the authorities.
And this is important because a "fair democratic society" that doesn't need people to be able to protest is, as history has shown many times, only a temporary affair. The best way to keep it is to not give the government the tools a worse government could use to suppress dissent.