I have to agree with DocJohn. I have previously liked or given hugs to someone's post, having no clue I was on ignore (having never even interacted with the member). Then one day went to actually comment on their post and saw I was blocked. So I know often it may just be the person doesn't know. Also, one of the challenging things here is that member, myself included, may ignore and un-ignore people depending on our own mental state and what we're going through. That's totally okay, but it can also mean that someone does or doesn't know they are okay to interact or not.

I also agree with OP, that, in my experience, you can also tell when someone is intentionally doing so. But we all have to share the planet together, even with people we'd prefer not to be in the same space as us. I like to think of it as practicing my own internal ignore button. Who cares if they comment? I don't have to read it or care. It can be good practice for that, as an upside.