What is the protocol for interacting with Facebook posts? I don’t think such a thing exists, but some seem to think so and interpret what happens in response to their posts according to their stated or unstated assumptions.
The posts that really annoy me are those that attempt to guilt you into responding. For example, those who generate a challenge in a negative way. “I bet I cannot get five responses to this post asking people to thank our vets”. I never react to such posts. I regard this as trolling for likes.
Facebook and other services that encourage likes, hearts, etc. operate according to behavioral principles. Likes are reinforcing and lead to more interaction with the services. The services are designed to “hook” users. People are looking for attention or affirmation and the number of pellets the Skinner box dispenses for them, the more frequently they press the lever.
This is an “eye of the beholder” issue. People read something into the frequency and identity of likes, etc. that often has little to do with the intentions of the viewers. In addition, because of the way Facebook decides who sees what, people do not have accurate knowledge of who even sees what they post. For me, likes are too easy and mean little. It would be easy enough to like every post. Does a like mean “I read it”? Does it mean “this is interesting”? Does it mean “I agree with you”? Facebook has even tried to offer multiple icons to make simple responses more meaningful. Some use these and some don’t. Does the angry face mean you agree with the author and are also angry or does it mean you think the author doesn’t have a clue? No protocol again. Comments require more effort and mean more to me. Other people think differently about these responses. I would prefer a meaningful argument to which I can respond.
My advice – post because you have something to say and are willing to make the effort to say it. Leave it at that.