A few observations:
1. An opinion is a conclusion. We are all entitled to ours, whether we choose to adorn them or not.
2. There is not, generally speaking, a universal reason for liking or not liking something.
3. Particularly on a message board, and particularly in 2021, it can be useful to examine the reason a person likes or dislikes something. Otherwise, the opinion can be of no value. E.g., if you tell me you hate a particular musical, but you do not tell me that you hate all musicals, you have failed to inform my understanding of your reason. Likewise, any prejudice, bias, lack of awareness, etc., for or against [or of] the subject of an opinion, is important if the intention is (as one would hope) to engage in a intellectually meaningful discussion.
4. When one person suggests that the other person's opinion reflects a failure to understand (or get) something, the insistence of the former that they DO understand, without embellishment, is not a meaningful engagement.
5. There are no "biggies" here. Yet most of us come here to understand things better than we did on our own. When someone states that what they are saying is "just an opinion," they are diminishing the potential value of a discussion.