FeetiePJs

It looks like this would apply to any item used to conceal one’s identity. So, it’s possible that all of those things could be included.

Exactly. So I think it would have been more helpful to just jump to the explanation. Just say “But protests are meant to be disruptive because that is how they draw attention to the issue being protested.” There is no need to question the knowledge of the commenter. Just present the information that you think they don’t have. Even if the person you’re replying to isn’t interested, the info will be there for others and may lead to more conversation.

do you know how protests work

This does not sound like an honest attempt at communication. Why would you even ask this unless you thought the person did not know? Yet you don’t offer any explanation of how you think protests work that might actually create a conversation. It may not be what you intended, but I interpreted your question as nothing more than a personal insult to the person who made the original comment. The equivalent of replying, “you don’t know what you’re talking about.” That sort of reply might be true, and I would probably even agree with it in the comment you linked, but it’s still not helpful in any way and kind of makes you seem like a jerk looking for an argument. So, to answer your question, I will often downvote a comment like this because it does nothing to make a positive contribution, and I would likely not explain why because I try to limit my interactions with people who are acting like argumentative jerks.