Earlier quoted context omitted.
It has a real "snitches get stiches" vibe to it. You have no expectation of privacy if you announce (let alone advocate for, or instruct how-to) behaviour against public health policy _during_a_pandemic_. The contrast with people who have been working hard to match people with appointments couldn't be more stark.
At this point in the US, anyone who wants to get a vaccine can get one. That makes getting it a personal choice. Then you have this person try to damage Ycombinator because one of their founders spoke internally about the matter. Absolutely tactless. You'd expect future founders to be able to consider potential repercussions for biting the hand that's serving them.
But since this all happened in March, when not anyone who wanted to get the vaccine could get any, your comment is irrelevant.