Because that is now the white power sign. That's reality now.
My point is very simple, and it goes for blogs, Twitter, Facebook, or bumper stickers on your truck: there's a lot of people out there who looking for the barest thing to fixate upon to get you in trouble, right down to a simple knuckle-crack.
I'll be blunt: I think it's very unlikely that your opinions on <insert current controversial topic> are going to revolutionize the status of the debate on that topic. The world has nothing to gain by you writing about that topic, and as you say, there's a chance you have something to lose. So just don't write about that. My advice if you want to maintain a blog is to write about something you care about and know about.
You can view my personal blog if you like, it's in my profile. I write about woodworking and video games and gardening. No one has tried to destroy my life for my experiences with growing grapevines. Sure, if I went off on a rant about <insert controversial topic> or wrote a bunch of hyper-negative invective about <insert group of people>, yeah that might come back to bite me. So I don't.
No one's going to come after you for a personal blog about playing guitar or whatever. Stay positive. Stay constructive. Stick to what you know. Don't invite controversy. You'll be fine, and maybe you'll even create something that touches someone else in a positive way.
https://www.nbcsandiego.com/news/local/sdge-worker-fired-ove...
There. It happened. In the real world. So cracking your knuckles is there under "inviting controversy."