Is having a personal blog that addresses controversial political topics possibly damaging to an academic career?
Let's start with this: as a professor you will be in a position of power over quite a few people. Part of the job of being a professor is to responsibly manage a number of employees and respectfully interact with students. If you really did (recently) practice hate speech, then that does legitimately disqualify you. 

However, when this becomes an issue you will probably never hear about it. Think about that from the position of the hiring committee: They have a number of applicants, most will be somewhat suitable for the job, but one will be stronger on one point and another stronger on another. So there are so many ways in which you can justify any decision. So when you do write down the justification, you will choose the one that will give the least problems.