There is nothing wrong with constructive criticism, and you have the right to say whatever you want. But people also have the right to be upset by what you say, even though you are completely allowed to say it. So just because you CAN say something, think, do you really need to?
I love reviewing and giving constructive criticism if I can, so I understand why you'd feel... bad? Unappreciated, perhaps.
There is something else I'd like to say but I won't because it could be upsetting for you. So I'll just leave it there.
Author's response
You can say it if you want, I don't care. I got music on so I'm alright.