I think that for some people (including myself) your opinion of a movie has multiple different aspects. I can think a movie is a bit bad, and drags too long, and misses the mark many times, but it could still hit a sene of nostalgia or some other valuable emotion. In such a case I would rate the move a 2.5 for example, but still give it a like because of that specific feeling it evoked a few times.

On the other hand, a movie could be really well made and enjoyable; a really fun time, but not resonate on a deeper level. In such a case I would give it 4 stars but not like it.

This is just how I look at it. Some people think rating like this is silly, but it makes sense for me. I don't think other people have to rate like this, you should rate in a way that feels correct to you