First off, thanks for the resteem!
You make a great point.
we want to show our support for a post but don't have the time/will to really dissect and write an intense analytical comment
I look for exactly the same thing being posted repeatedly. You can personalize any comment in 2 seconds if you're literally typing it into the form, the issue is when you're copy/pasting it again and again and that's really all I see, and only if you do it a lot.
Even so, you highlight the discretion necessary to properly identify these comments, which is why nothing is automated today and I manually review everything. You ask where to draw the line between spam and a simple comment and that is probably the most difficult question I face, so for now I err on the side of caution and comment only the most obvious offenders.
I genuinely appreciate your support and willingness to share your thoughts here!