I wouldn't flag such comments.. First of all, how one should know was this general comment made with or without reading the article? Maybe a person just has no personal opinion on a certain post, for example. I have some authors who I know from loong time ago an Steemit who write on some scientific stuff which is quite hard to understand. At the same time I don't vote on posts I don't read [except a very few authors I upvote automatically from a long time ago]. So I read a scientific post, understand not so much, but to support an author I upvote a post and leave some kind of a generic comment.
Or another situation. As I have not so many comments under my posts - I always read them and then check the profile of the author. If there's a post at least to some extent worth voting, I vote for it and usually leave a comment. And sometimes it's hard to leave a specific comment because the article itself was kind of not so thought-provoking.
Just my thoughts, your comment was provoking. :D
I think a pointless comment saying you liked it or whatever is usually better left unsaid with just an upvote. Unless maybe it's an article that doesn't have any comments yet, everyone appreciates a comment. Though usually I get excited that someone commented and then I see that it is just something like "nice post!" or "Thanks for sharing" or something pointless and I am just annoyed. haha. I always try to add something to the discussion or just leave it at an upvote
Okay, not so generic comments :D :D I leave such comments only as a reply on generic comments to my posts. 😕
Otherwise I also try to add to the discussion.
It's difficult though to add something to breathtaking photos, still. 😊 No words will help.