I fully agree with you. neither "like" or "dislike" have any meaning unless they come with some explanation of why this is so. If you do not have the time or energy to seriously think about something, why comment at all?

My son taught me this lesson many years ago. He came one day from school with a drawing he made and proudly gave it to me. "what a beautiful drawing" I said briefly glancing at it, being pre-occupied with something that was on my mind at that moment. "Mom" he said " How can you say it's beautiful, when you didn't even look at it?" . So, from that day on I have learned my lesson. My son is not going to accept from me superficial answers to anything.