Do they? I've mentioned homeschooling on hn before without issue. There's always knobs who can't have a nuanced view of course, but generally the discussions I've seen have tended positive.
But yeah I get your point that it's like there's an unreasonable number of people who have a strong opinion on it despite having no actual experience or evidence or reason to comment. Homeschool is a small minority and the majority are biased to what they know. We homeschool 3 kids, didn't intend to to it before it happened, and I would have held some very incorrect opinions about it too, for what little thought I ever actually gave it.
I was surprised at how much negativity surrounded the topic, despite what feels like a general dissatisfaction with the public schools at this time.