This question already has an answer here:
- How do comments work? 1 answer
I can't comment the original post (red rectangle) and I don't know why.
I can comment the other ones.
What I can't do:
Who can post comments?
Since your user don't have 50 reputation, you can't, for now. But getting 50 reputation on Stackoverflow is not so hard ;)
And don't worry about downvotes. Because upvotes and downvotes different on meta.