at the cost of straying from your TRUE reasons for liking/disliking...For example, maybe you really like Movie A just because you found it entertaining

That doesn't count as a true reason. In fact, it is no more than a restatement of the fact that you like it. If you didn't find it entertaining, then that means you found it boring, which is incompatible with liking it. (Can you imagine anyone saying "I found this movie boring, but I liked it anyway?")

To say "I just found it entertaining" as an answer to the question of why one likes something is not an honest-but-unspecific answer; it is an outright dodge.

(If anything, it's a weaker statement than saying you like it, because one could conceivably dislike something despite not being bored by it.)