Weird Facebook “Reactions” Question

Okay, so there’s this guy on a public Facebook forum that posts all kinds of nonsense (nothing new, right). Anyway, he is able to block those of us who disagree with him from 1) Using any reactions 2) Replying in comment form.

Now, I’m wondering - since I cannot react to his public posts — can I do this also? If so — how?

Thanks ever so much,

Patrish LaDish