If you have comments open on your blog, on a long enough timeline the odds of someone posting something snide asymptotically approach 1. When I ran Ganriki.org (it's currently in hibernation), I'd sometimes get snotty remarks. Eventually I figured out almost none of this stuff is worth replying to, even if the other guy has a grain of truth in what they say. Just because someone is right like a stopped clock doesn't mean you're obliged to engage. Take the insight and move on.
The people most worth arguing with — and I mean "argue" in the constructive sense — are people I already know to some degree, already trust to act in good faith, and already allow me the freedom to be wrong without it also being a moral failing. I have never felt like I missed out on something when I chose not to yell back at strangers.
I made a decision a while ago about this blog. I decided that unless I felt qualified and competent to comment on some current event, I wouldn't do so. (To use a timely example: I am not an expert on Middle Eastern affairs. Nothing I say on that subject would be of much use to anyone.) I decided to focus my discussions here on what is actually in front of me — my writing, my allied creative projects, my adventures in such work overall, etc.
Nobody with any kind of public presence should be obliged to comment on absolutely everything that's news-worthy. Not everyone has something constructive to say. Not everyone has something to say that hasn't been said better by others elsewhere. Just because someone is well-known doesn't mean they have useful insight into an issue. And no one who chooses to stay in their lane should be made to feel bad about it. If the purpose of such things is to get them involved, perhaps they already are involved, and simply choose not to talk about it. Why rush to assume bad faith or indifference?
Unfortunately, I do have an answer to that question. Some people simply want an argument at any cost. And too many of us have the unchallenged assumption that we're losers if we walk away from a fight, even if it's one that is designed not to be won. There are more productive uses of all our time.