‘Liking as acknowledgement’ is similar to how I use the feature. For me it means “I read what you said and it pleases me that you wrote it.” It isn’t a deeper analysis of what you said, which is what I feel a comment is for.

That being said, I won’t ‘like’ something, not even an honest opinion, if I have an immediate negative reaction to it. I won’t click the like button if someone posts “I like to eat children: they are crunchy and make interesting noises while being cooked.”